TYPES OF OPALS

Australia mines 97% of the world's different types of Opals. The other 3% come from Mexico, Brazil, Ethiopia and Hungary but are not the same quality that Australian Opal is world renowned for. The Australian Opal fields were once an inland sea. As the ages passed and the seas receded, sea creatures were isolated, marooned, and Opalised. Eventually the area dried out completely and is now dry desert country. In time the ground waters, holding silica solution, also evaporated (with some artesian springs still active deep "underground"). In a few spots they left behind the phenomenon known as 'Opal'.

  SHOP NOW

 

BLACK OPALS

Australian Black Opal from Lightning Ridge N.S.W. is the most famous form of Opal in Australia. Hand Cut in Sydney N.S.W. loose Black Opals with Gem colour and a "named" pattern are 5000x rarer than diamond.

Indigenous Aboriginal Elders from the Yolgnu tribes in Arnhemland say that when the earth was covered with water the great creator spirit "Garray" created the rainbow as a promise of His great love for balirrpalirr (the spirit of mankind). The mokuy (evil spirits) were Jealous of this love and caused a terrible drought so that the rainbow would never be seen by the beloved balirrpalirr. Garray however placed the rainbow inside a stone and hid it in the ground, hididn the gift for future generations. The mokuy looked everywhere but could not find it. This is djari banda (Rainbow Stone) and is considered to be the Garray Gunda - The Creators Gemstone!

A rainbow in the sky is formed because water molecules are trapped in air. In Opal the water molecules are trapped in-between silica molecules. So Australian Opal is literally a rainbow that has been transformed into a gemstone. The water in the silica is stationary rather than moving. The Australian Opal fields were once an inland sea. As the ages passed and the seas receded, sea creatures were isolated and marooned, and Opalised. Eventually the area dried out completely and is now dry desert country. In time the ground waters, holding silica solution, also evaporated (with some artesian springs still active deep "underground").

Black Opal is formed as water runs down through the earth picking up silica from sandstone. This silica-rich solution is then carried into cracks and voids, caused by natural faults or decomposing fossils. As the water evaporates, it leaves behind a silica deposit. The deposit eventually hardens to form common Opal, and in rare circumstances it forms precious Opal.

The most valuable and popular of all Opals is Black Opal. Black Opal accounts for around 5% and is found at Lightning Ridge in Northern NSW. It is called Black Opal because it has a black base caused by black or grey iron oxide impurities in the Opal.

The color bar or the 'play of color' of Black Opal comes in all the colours of a rainbow with red being the rarest and most expensive. A Black Opal is Crystal Opal with iron oxide in the back. It can be grey through to very black. This black potch or common Opal has no value unless we find a color bar on top of it. It's all about the evidence we get when we cut rough Opal, we find a little piece of color on the side and we take off the top layer of potch (common Opal) and we hope the Opal faces up. Then we take off the skin of the stone and we hope we get a face with nice color. Often it looks very nice on the side but not on the face, that is the risk we take in cutting black Opal. The yield when we cut black or Boulder Opal is 5% that means we lose 95% of the Opal, it is very risky to buy rough black Opal and cut it.

Black Opal is incredibly rare and is found at Lightning Ridge in Northern NSW, so called because in a terrible storm a farmer, his dog, and 600 sheep were all killed by lightning. The name 'Black Opal' is derived from its black base caused by black or grey iron oxide in the Opal. This black potch or common Opal has no value unless we find a colour bar on top of it. The colour bar (or the 'play of colour') of Black Opal comes in all the colours of a rainbow with red being the rarest.

The "Variety" of an Opal is determined by where the Opal Body Tone is located within the Body Tone Chart, which is a chart that the Opal industry recognises as the definition of the "black-base-tone" in a Black Opal. Opal that has a body tone of N1-N4 is defined as "Black Opal". Opals mined in the "Mintabie" fields in South Australia have been known to produce excellent quality Black Opal however are more famous for "Dark Opal" or "semi-Black" or "Grey" Opal, terms used to describe Opals with body tones lighter than N4.

Whether an Opal is a black or not can be determined by merely examining the face of the stone. All colours are ignored and the overall body tone (blackness level) is estimated. This is compared to the scale of blackness shown below stones achieving values of N1 to N4 on this scale are considered Black Opals - attracting the additional value associated of this class of Opal.

Natural Opal is Opal which has not been treated or enhanced in any way other than by cutting and polishing. There are three types of natural Opal. The "Type" of Opal is determined by analysing the Opal is "Solid" hydrated Silica or if it is dispersed with an ironstone host.

Natural Opal Type 1 - is Opal presented in one piece in its natural state apart from cutting or polishing, and is of substantially homogenous chemical composition.

Natural Opal Type 2 - is Opal presented in one piece where the Opal is naturally attached to the host rock in which it was formed and the host rock is of a different chemical composition. This Opal is commonly known as boulder Opal.

Natural Opal Type 3 - is Opal presented in one piece where the Opal is intimately diffused as infillings of pores or holes or between grains of the host rock in which it was formed. This Opal is commonly known as matrix Opal.

A variety of tools are needed to mine the Opals, some more complex or more effective than others.

There has been a rapid increase in the use of mining machines since the 1970s. Tunneling machines with revolving cutting heads and small underground front-end loaders (boggers) have been introduced to streamline Opal mining and dramatically increase productivity.

Miners soon saw the benefits of technology - drilling test shafts to gauge their chances before beginning serious excavation, using jackhammers instead of pickaxes, blasting with dynamite, or bringing in the bulldozers. Bulldozers are employed to remove overburden and expose the level where it is shallow. Spotters follow behind watching for traces of Opal, and any seam found is then worked over by handpick.

Of course, all of these labour savers sometimes end in bitter tears, when the Opal is spotted only after it has been shattered. They also increase the cost of equipment and operation.

‘Sinking a shaft’ is one of the most laborious methods of mining. The length of the shaft could be as short as 3 metres or as long as 20 metres but it does save the miners the several days it could take to reach Opal level by hand.

Natural Black Opal (Type 1) is the most valuable and popular of all Opals!. It is called Black Opal because it has a black base caused by black or grey iron oxide in the Opal. This black potch or common Opal has no value unless we find a colour bar on top of it. The color bar or the ‘play of colour’ of Black Opal comes in all the colours of the rainbow with red being the rarest and most expensive and may be designated N1, N2, N3 or N4 on the Scale of Body Tone.

Black Opal has a blue-black to light charcoal body tone and is vary rarely found outside Lightning Ridge in New South Wales.

The dark background serves to highlight the colour-play of dramatic spectral flashes. Fine examples of this variety are the most expensive per carat and rival rare pink and red diamonds in price. Black Opal is found as what the miners call ‘Nobbies’, these are fossil replacements of corals or sponges. During its formation, the replacement of organic material by Silica resulted in carbonaceous material or impurities like titanium impregnating the mineral structure giving Black Opal its body colour.

With names like Harlequin Street, Silia Street, Opal Street, Agate Street and Nobby Road, Lightning Ridge is a very small area dotted with small mines run by individual enthusiasts, hobbyists, ‘mum-and-dad’ miners and those who have caught ‘Opal Fever’ and have never been able to leave the addictive allure of finding that million dollar gemstone.

Genuine Natural Australian Black Opal consists of a hydrated amorphous form of concretions of SiO2·nH2O silica consisting of spheres of silicon dioxide molecules arranged in regular, closely packed planes. Black Opal can only be found at Lightning Ridge in N.S.W. Australia. Black Opal is a diminishing resource with anecdotal evidence suggesting increases in value of up to 15% per annum. Australian Opal Cutters Black Opal is Guaranteed to be free of dyes and artificial colour.

Valuing Opal is extremely complex! Forget the “4 C’s” Opal requires the detailed examination of over 13 characteristics to assess value:

Variety, Body Tone, Brightness, Transparency, Colour, Hue, Outline or Shape, Profile or Cut, Patterns, Display (Directional or Multidirectional), Distribution of colour (%), Inclusions/Clarity and Carat Weight.

However if you just remember the “Miners Test” you can know if your Opal is a true gem. Take your Opal out of the bright light and just “cup” it in your hand to shade it slightly. If you see red “fire” or green “fire” you will know that you have an authentic gem!

Opal is an extremely precious gem. Black Opal is possibly 130 times rarer than diamond! For every 130 million carats of diamond produced only 1 million carats (or 200 kg) of Opal is mined. And from this rough the loss factor in cutting can be as high as 95 (in black Opal).

You may have heard that “Tanzanite is 1000 x rarer than diamond”. This is suggested because there are 100 miles of tanzanite mines worldwide, and when compared to the 100,000 miles of is 1000 x rarer than diamond”. As there is only 20 square miles of black Opal mining black Opal is actually 5000 x rarer than diamond.

Opal is a diminishing resource and there is anecdotal evidence that suggests an increase of up to 25 % per annum in boulder Opal prices and 15 per annum increases in white, crystal and black Opal. The value of an Opal purchase is established when you purchase it as, compared to diamond, ALL Opals are sold for much less than their true worth.

The type, colour, size and soundness of precious Opal are factors that determine the price paid for the gemstone. The price is based on the quality of the Opal and expressed per carat. Furthermore, there is a marked difference between the value of uncut Opal compared with the value of cut and polished Opal. Categories such as the variety, background, transparency, spectrum, tone, origin, distribution, inclusions, carat weight etc. all add to determining the correct value of the Opal itself.

The clarity of the colour is critical when assessing the value of Opal. Red fire is the rarest colour, followed by green/orange, green/blue and blue. Therefore red fire Opal is generally more valuable than a predominantly green Opal, which in turn is more valuable than a stone showing only blue colour.

However, brilliance and clarity of an open proportioned pattern are the main decision makers - a brilliant blue/green can cost more than a dull red; bright twinkling stars of a ‘pin fire’ pattern can cost more than a cloudy open pattern of similar colouration; or a brilliant, lustrous light Opal can cost more than a lacklustre black Opal.

The majority of us are not experts nor could we value an Opal just by looking at it but there are 3 main things we can look for that can give us a clue on how valuable an Opal can be:

MULTI-DIRECTIONAL COLOUR
If the Opal colours change with the shift of light

PATTERN
Large blocks of colour is the preferred pattern

FIRE
If an Opal has true fire, it will shine even in the shade

A full analysis of an Opal however requires the study of all of the characteristics of the Opal. This is the only way to truly determine the value.

Any “valuation” that does not analyse the full spectrum of value characteristics and provide examples to prove the assessment is not a true assessment and should be disregarded.

BOULDER OPALS

Queensland Boulder Opal, ‘freeform, asymmetrical ‘carved’ Opal. Loved for its uniqueness, individuality, beauty and rarity Boulder Opal is a genuine investment. Boulder Opal is completely ‘Natural’ or free of dyes, colour enhancing chemicals, heat or radiation treatments. Each and every Boulder Opal ring, pendant or earring pair is quite literally the only one of its kind as they as each Boulder Opal is absolutely unique due to the free-form cut and colour formation.

The Boulder Opal is arguably one of the rarest and most valuable forms of Opal found in Australia and makes up less than 5% of all Opal mined. It is very sparsely distributed through South West Queensland. It is predicted that Boulder Opal is going to run out in the next 10 years because of the difficulty clearing Native Title and EPA requirements of rehabilitation. Native Title is the process of gaining agreement from the local Aboriginal tribes before mining takes place. This is an extremely difficult and time consuming process. Added to this is the EPA requirement that all mines need to be “back-filled” and trees planted when the mining is finished. This process alone can send a miner bankrupt if he has not found “colour” in his “dig”. Added to this are the onerous paperwork requirements, with “enough forms to sink a ship” the average miner just does not have the motivation to comply with all of the government regulations. So, as a result there are fewer and fewer miners on the field!

Boulder Opal is formed in the cracks and crevices of the ironstone Boulders in a gel form possibly as recently as hundreds of years ago, and with the passing of centuries this jelly Opal turned solid and as you can see we are left with some beautiful Boulder Opal specimens. Boulder Opal occurs as a filling between the concentric layers or in random crevices in the ironstone. The cutting process is extremely difficult as the cutter must navigate the “hills and valleys” of the Boulder Opal surface. What we are left with is an incredibly unique and individual gemstone.

The Boulder Opal has a high loss factor when cutting as we only yield 5% and has a rock waste factor of 95%. It is also the only Opal suggested to run out within the next 5 to 10 years and with the value (“it is suggested”) increasing by 15-25% each year the Boulder Opal can certainly make a sound long term investment.

Boulder Opal is found in the barren, dry, inhospitable region in central Queensland. Found in the "shincracker" layer (resilient Boulder Opal Ironstone). A "spotter" will fly through the desert on a dirt-bike at up to 80kmn per hour looking for "show" (Boulder Opal Ironstone that is visible above the surface). A peg is placed in the ground and then a swimming-pool size hole is excavated. The Opal colour fills microscopic cracks and crevices in a process that is still regarded as a “miraculous” process. To reveal the colour the Ironstone has to be hand-carved by a master gem cutter, a process that is both difficult and time consuming.

Once the Opal is mined everything is back filled and trees are planted creating

a beautiful oasis in the desert, and one that has produced arguably the worlds most valuable commercially available gemstone!

Boulder Opal is an absolutely magnificent gemstone. Arguably the rarest of all Opal gems Boulder Opal is a diminishing resource (which means it is genuinely running out). Each Opal is unique, each gemstone is hand-carved from 'veins' of Opal colour that ebb and flow through the heart of the ironstone. Boulder Opal pendants are designed around the incredible beauty that occurs within the free-flowing surface of the Opal with the Gemstones natural 'Ironstone' often appearing on the surface (which adds character and individuality) Boulder Opal Pendants are an absolutely unique gift. Individual, creative, expressive they reflect the absolute miracle that is natural Opal Formation

Boulder Opal was first discovered in a small town called Blackall in central Queensland, Australia in 1869. Many discoveries were made during the 1870’s but it wasn’t until the 1890’s when Boulder Opal was introduced in Europe and has gradually gained its name & its value in the gem industry.

Boulder Opals are easily distinguished by their layer of solid brown ironstone left on the back of the stone. Boulder Opals, as the name suggests, are mined from large ironstone Boulders under the ground. Thin veins of colourful Opal forms in cracks and fissures in these Boulders.

Arguably the rarest of all Opal gems Boulder Opal is a diminishing resource (which means it is genuinely running out). Each Opal is unique, each Australian Opal Cutters Boulder Opal gemstone is hand-carved from 'veins' of Opal colour that ebb and flow through the heart of the ironstone. A Boulder Opal ring is a genuinely unique, individual and collectible piece of bespoke Jewellery so it is very difficult to describe. This is one of the benefits of owning a Boulder Opal, there is only one of each! They are genuinely on-of-a-kind pieces due to the absolutely organic and natural way the colour flows through the cracks and crevases as well as the incredible and amazing colour play.

Boulder Opal rings in silver, gold, white gold or platinum are absolutely stunning. Because each Boulder Opal has a unique shape and colour each ring is individual and never to be repeated. This is in stark contrast to the bulk of other gemstones. Sapphires, Rubies, Diamonds and many other gems are beautiful and valuable yet each gem is fairly indistinguishable from any other gem in their category as gems are basically all very similar. There are (of course) differences that separate and define value, but as a whole they ‘basically look the same’. Boulder Opal is exceptional as they are so incredibly unique. In each Boulder Opal there is a world of discovery as the colour and shapes ebb and flow in absolutely unique patterns and colours in every gem. This makes wearing a Boulder Opal ring a very precious and individual experience, and one that will always receive endless compliments and comments of admiration from friends and colleagues.

There is no solid scientific explanation as to how the hydrated silica forms in the ground, however, there is a general consensus as to how the actual gemstone is created. As it is permeating into these cracks and crevices, there is occasionally a hole that is formed by a gap, fissure or crack being opened up within the layers of the Boulder Opal (or, with crystal opal foreign element such as a marine dinosaur such as squid bone, small pieces of wood, or a shell).

Although carbonated materials usually fill these holes, occasionally hydrated silica of the Opal has filled the hole and solidified. This process is a rare occurrence, and as a result, there is limited potential for a miner to find Opalised material filling what would otherwise be ‘cracks’ or ‘crevasses’ in the Boulder Opal.

Genuine Natural Australian Boulder Opal consists of a hydrated amorphous form of concretions of SiO2·nH2O silica consisting of spheres of silicon dioxide molecules arranged in regular, closely packed planes filling the cracks and crevices of Boulder Opal ironstone found remotely in Queensland Australia. Boulder Opal is a diminishing resource with anecdotal evidence suggesting increases in value of up to 15% per annum. Guaranteed free of dyes and artificial colour.

Boulder Opal is incredibly rare due to multiple factors, including the limited amount that can be mined, and the high loss factor that is experienced when cutting (only yielding 5% of what is brought in), subsequently resulting in a diminished market. As a gem, Boulder Opal is significantly increasing in value, as the amount currently circulating is only finite, and therefore is suggested to run out in the next 5-10 years.

In the 1980’s there were approximately 200 miners working the Boulder Opal fields in Queensland. This figure has dropped dramatically as there is now a mere handful (estimated to be only 20 miners in 2018). There are two main factors for this change. The first is a natural resource mining boom that Australia has experienced in the exploration of Oil, Gas and other ores. Opal miners earn ‘big money’ and are leaving the fields for this reason.

Secondly On average, Opals with a darker tone are considered to be more valuable in comparison to lighter variants. This is mainly due to the fact that a darker stone will display the colours on its surface with more intensity, making them more vibrant than a white stone that may have the same hues.

WHITE OPALS

Opal is Australia’s National gemstone and White Opal is the most famous form of Australian Opal and most seen in a ring, pendant or earrings. White opal is mined in South Australia and is easily distinguishable from other types of opal due to its lighter colouration. The white tone is a result of magnesium oxide in the silica and is often described as a ‘pale white’ or a ‘milky’ complexion. This type of opal is more common in comparison to others, however that doesn’t stop it from being truly beautiful and valuable.

Coober Pedy was discovered in 1915. This is where most of the 'white' or 'milky' and crystal opals (together known as 'light opal') are mined. Coober Pedy is the main producer of white precious opal, which is predominantly seen in stores overseas, particularly in the USA. Today, the opal fields encompass an area of approximately 45 kilometres. The opal level is formed of soft pinkish clay mixed with soft bleached sandstone.

The name “Coober Pedy” is an Aboriginal word that translates “man in a hole” and with temperatures around 40 degrees Celsius or 100 degrees Fahrenheit all year the cool underground mines have become popular as living quarters, and now most of the locals live underground!

The name opal was probably derived from a Sanskrit description of white Opal "upala", meaning "valuable stone" or from the Greek word "opallus" which means to see a change in color. The most likely location for the original Roman or Indian connection to Opal were the small quantities mined for centuries in Hungary.

Later, the Latin word "opalus" evolved, meaning precious stone. In the days of Roman antiquity there existed a so-called "opalus", or a "stone from several elements". Pliny the Elder, the famous Roman author, called opal a gemstone which combines the best possible characteristics of the most beautiful of gemstones; the fine sparkle of almandine, the shining purple of amethyst, the golden yellow of topaz, and the deep blue of sapphire, "so that all colors shine and sparkle together in a beautiful combination".

These “white” Opals were considered to be incredibly valuable and powerful by the ancient Romans.

Australian White opal was discovered at Coober Pedy in 1915; most of the opals classified as ‘white’, ‘mily’, or ‘crystal’ are mined at this location, even today. As a result of this, Coober Pedy is the main producer of this precious stone, and therefore exports of such stones often originate from this location.

Genuine Natural Australian White Opal consists of a hydrated amorphous form of concretions of SiO2·nH2O silica consisting of spheres of silicon dioxide molecules arranged in regular, closely packed planes filling the pockets and cavities left behind by dissolved mineral deposits, fossils or plant material in Coober Pedy in South Australia. White Opal is a diminishing resource with anecdotal evidence suggesting increases in value of up to 7% per annum. Australian Opal Cutters White Opals are Guaranteed free of dyes and artificial colour.

When compared to other opals, white opal is the least valuable. This is because they are a common form of opal to be found, in addition to their light colouring, as the darkness within an opals stone leads to the more vibrant colour (as can be seen in boulder opals and black opals).

CRYSTAL OPALS

Fossilised Opal, translucent, transparent Crystal Opal is found in South Australia and NSW and is incredibly rare and beautiful.

Crystal opal is pure hydrated silica, or pure Opal. It does not contain any oxides (the material that turns an Opal white or Black); Crystal Opal is translucent so you can see straight through it when you hold it up to a bright light.

Crystal Opal often exhibits many of the most sought after (most valuable) traits when valuing an opal. The colour is usually multi-directional (meaning, colour can be seen from many different angles), with large blocks of colour that can be vibrant enough to see in very low light.

A classic ‘test’ used on the Opal fields is to take an Opal and “cup” (hold) it in one hand as you move the Opal out of the direct light. Viewing the Opal in the ‘semi-dark’ or shadows allows the miner to really test the intensity of the colour (the “hue” and/or “Brightness”) which are two of the valuation characteristics. This is called the “miners test” and is a great (and simple) way to ‘test’ an Opal.

All Opals have a “crystalline’ structure so the the name ‘Crystal” is a reference to the translucent appearance as opposed to the structure being different to any other form of Opal (as the molecular structure and chemical composition is basically the same). Other forms of Opal (such as Boulder, Black and White Opal) can all display the trait of crystalline translucency are not not called ‘crystal’, with Boulder Opal this is because they have the ironstone base. A Black Opal that is translucent may be known as a “Black Crystal”

The translucence of these gems often increases the vibrancy of colours, as light can easily pass through accentuating the rainbow diffraction effect. The nature and shape of the stone will also have a great impact on the colour exhibited, crystal opals are therefore often ‘carved’ to maximise the amount of Opal that can be extracted from the rough Opal material and maximise the display through volume. Traditionally either a standard ‘oval’ shape, ‘round’ or a ‘teardrop’ shape was the “standard” from the 1890’2 through to the 1960’s. “Carving” was really adventurous but far more common today.

While crystal Opals can occur in very limited quantities in all of the Opal fields (even boulder Opal can show translucent crystal Opal forming in the seams, cracks and crevices, These opals are usually found and mined in South Australia in a field called Andamooka.

Genuine Natural Australian Crystal Opal occurs in limited quantity in all of the Australian Opal fields (Andamooka, Lightning Ridge in NSW, Coober Pedy in South Australia and the Queensland Boulder Opal Fields). A hydrated amorphous form of silica SiO2·nH2O consisting of spheres of silicon dioxide molecules arranged in regular, closely packed planes. The Opal is pure hydrated silica SiO2·nH2O “free” from oxides (Magnezium) so it has a clear translucency. Precious Crystal Opal shows a variable interplay of internal colors, and though it is a mineraloid, it has an internal structure. At microscopic scales, precious opal is composed of silica spheres some 150 to 300 nm in diameter in a hexagonal or cubic close-packed lattice. It was shown by J. V. Sanders in the mid-1960s that these ordered silica spheres produce the internal colors by causing the interference and diffraction of light passing through the microstructure of the opal. The regularity of the sizes and the packing of these spheres determines the quality of precious Opal. Where the distance between the regularly packed planes of spheres is around half the wavelength of a component of visible light, the light of that wavelength may be subject to diffraction from the grating created by the stacked planes. As one time central Australia was filled with a great inland sea (known as the Artesian Basin) Plant matter, marine life was trapped and deposited in the sediment as this sea receeded. As a result of this Crystal Opal material has formed from fossilised shell gastropods, Belemnites and other dinosaur vertebra.

Science

Dinosaurs and other ancient creatures once inhabited a great Inland Sea in the heart of the Australian Outback (The Artesian Basin, where Lightning Ridge is now located). These ancient reptiles swam in this sea which covered much of inland Australia and the opal fields of White Cliffs, Coober Pedy, Andamooka, Mintabie and Lambina are now filled with many of the fossilised remains of these great prehistoric sea creatures.

Many of the incredible Crystal Opals are formed from these dinosaur plants and bones. They are Australian National Treasures, of global scientific interest, and among the most beautiful and valuable fossils in the world.

Crystal Opal fossils form in cavities within rocks. If the cavity is there because part of a living thing – for example a bone, shell or pinecone – was buried in the sand or clay before it turned to stone, then the opal can form a fossil replica of the object that was buried.

A fossil is simply “the remains or traces of an ancient animal or plant preserved in rock”. Opalised fossils form in ways similar to other fossils, except that here they are preserved in silica. Elsewhere, fossils are preserved in minerals such as agate, pyrite or limestone.

The sediments that buried plant and animal remains in the opal fields were rich in silica from ancient volcanoes, so here we have fossils preserved as silica in the form of opal.

Opalisation of plants and animal remains happens in two ways, and at Lightning Ridge, a combination of the following two processes is seen in many specimens.

Internal details are sometimes not preserved (‘jelly mould’ fossils). Opal starts as silica dissolved in water. When the silica solution fills an empty cavity left by a shell or bone that has rotted away (like jelly poured in a mould) it may harden to form an opalised cast of the original object. In these fossils, outside features can be beautifully preserved, but the internal structures are not recorded.

In rare cases the Internal details are preserved. If the silica seeps into the organic material before it decomposes, then the organic molecules can be replaced by silica. This preserves very fine details of structures inside the bone or plant. When the silica is transparent, this internal anatomy is visible from the outside: the fossil is ‘see through’.

These can be the most valuable of all crystal Opals and can be incredibly beautiful! They provide new and fascinating information about Australia's ancient heritage and the types of plants, animals and environments on the Australian continent.

Of all the Australian opal fields, Lightning Ridge and some boulder opal fields are the only places that have opalised fossils of land-living and freshwater plants and animals. The other Australian opal fields have fossils of saltwater or marine organisms, which provide other important information about Australia's past and the ancient Eromanga Sea.

Australia is the only place on earth that produces opalised bones of land-living animals including dinosaurs – and most of these are from Lightning Ridge.

Lightning Ridge is the only significant dinosaur site in New South Wales. Opalised bones from fields like Coober Pedy, Andamooka and White Cliffs are from plesiosaurs, ichthyosaurs and pliosaurs, which are marine reptiles, not dinosaurs. Fossils are preserved here in silica in the form of opal. Some of them are see-through, including the only transparent fossils of large animal bones in the world.

The Lightning Ridge fossils are of plants and animals that lived close to the South Pole, in global greenhouse conditions, in habitats unknown anywhere today. They are a window onto Australia’s past - important for scientists who study the origin of Australian plants, or dinosaurs, or mammals, or climate change, geology and many other aspects of earth history.

Fossil formation is closely linked to opal formation. Study of opalised fossils could provide important new information on opal formation, and help with opal exploration and prospecting.

Types of Opalised Fossils

Plants Tonnes of opalised plant fossil is extracted from Lightning Ridge opal mines each year. Although some is exquisitely preserved, most is too fragmentary to be informative – other than to show how richly vegetated the area once was.

Diverse pine cones, drupes, stems and seeds are found, sometimes glittering with gem colour. Lightning Ridge was once heavily forested with conifers such as Araucarian, podocarp and Kauri pine trees, towering over ferns, seed ferns and ground pines, fungi and lichens, mosses, liverworts and horsetails.

Large pieces of silicified wood are also found in the opal mines; however, these larger pieces are rarely opalised.

Molluscs Bivalve and gastropod molluscs (mussels and snails) are the most commonly-found opalised fossils at Lightning Ridge. The freshwater species found at Lightning Ridge differ from the molluscs found at White Cliffs and in South Australia, which lived in a marine environment.

Mines that intersect with palaeochannels sometimes contain rich deposits of bivalve molluscs. Occasionally, concentrations of whelks form dense death assemblages in sandstone.

Many different species of opalised mollusc have been found at Lightning Ridge. Although some are relatively common, others are rare.

Freshwater crayfish The opalised gastroliths of freshwater crayfish are known locally as ‘yabby buttons.’ Crayfish use gastroliths to store calcium from their exoskeletons (‘shells’) before they moult, then release the calcium to harden their new protective coating. Fossil yabby buttons are usually around 10-12mm across.

Sharks Fossil shark teeth are rare at Lightning Ridge. Nevertheless, their discovery from time to time suggests that at the time the opal-bearing sediments were laid down, Lightning Ridge wasn’t too far from the shore of the sea that covered much of inland Australia.

Lungfish At least three species of lungfish lived at Lightning Ridge in the Early Cretaceous period. We know them from the opalised toothplates found in the mines.

Bony fish A variety of freshwater bony fish from ancient Lightning Ridge have left traces of themselves as opalised fossils, mostly jaw bones and backbones. Relatively few have been recovered, probably because most are so small or fragile that they are not noticed, or are destroyed by the mining machinery.

Frogs The oldest frog fossil known in Australia is a tiny opalised upper jaw found in a mine at the Coocoran fields, Lightning Ridge.

Turtles Lightning Ridge’s fossils include at least three kinds of land- and swamp-living turtles, including the world’s oldest horned turtle (meiolaniid).

Crocodiles Three different species of crocodile have been identified so far among Lightning Ridge’s opalised fossils. All appear to have been from relatively small crocodiles. The Australian Opal Centre has teeth, back bones and scutes (bony armour from beneath the skin) of these ancient monsters

Plesiosaurs Plesiosaurs were swimming reptiles that lived during the dinosaur era – the 'reptilian seals' of their time. Some lived in the sea and some in fresh water. Some sea-living plesiosaurs swam upstream to breed. At Lightning Ridge, opalised plesiosaur teeth are found relatively commonly, but plesiosaur bones are extremely rare. The teeth indicate at least two different kinds of plesiosaur.

Dinosaurs Lightning Ridge is blessed with the opalised remains of several kinds of dinosaur: sauropods, theropods, ornithopods, ornithomimosaurids and ankylosaurs. They range in size from the ridiculously enormous to little chicken-sized dinos!

Opalised dinosaur teeth, limb bones, back bones, toe bones, claws and pieces of rib, pelvis and shoulder have all been discovered. Most are in grey, black or amber-coloured potch, but some shimmer with colour. In some opal mines you can even look up to see the underside of dinosaur footprints in the roof.

Pterosaurs Pterosaurs were flying reptiles that lived with the dinosaurs, went extinct with the dinosaurs and left no living relatives. Uncrushed pterosaur fossils are quite rare globally, because the bones were hollow and thin-walled. A small number of opalised pterosaur bones have been found at Lightning Ridge.

Snakes Snake bones are very delicate and fragile. So far we know of only one opalised snake fossil from Lightning Ridge – a tiny fragment of lower jaw – but as greater care is taken to retrieve tiny fossils from underground, it is likely that further snake fossils will be found.

Birds Just a few tiny bird bones have been found, and perhaps a bird tooth!

Mammals Lightning Ridge made the cover of the prestigious journal Nature when its first opalised monotreme mammal was found – the jaw of a platypus-like creature named Steropodon.

Since then, other rare but important monotreme fossils have been discovered, including vertebrae (back bones).

Quality crystal opals often result in a high value. This is because the overall clarity of the colours is a direct result of the shape, size, and type of stone, and is therefore unable to be replicated in other pieces, therefore giving the crystal opal a higher value than a ‘standard’ opaque opal.

Opal can shows a broad range of “diaphaneity” (transparency) that ranges from transparent to opaque. Natural precious opal (which is transparent to semi-transparent) is defined as “crystal opal”. Crystal opal can have either a black, dark or light body tone. In this context, the term ‘crystal’ refers to the appearance of the opal and not its crystalline structure. Crystal opals will often “face-up” more brilliantly against a black background (which enhances the brilliance of these opals’ play-of-colour). The same crystal opal shown against a reflective (or white) background will often “subdue” the opal’s “play-of-colour”. When purchasing an Opal on the internet it is important to see the Opal displayed against a black background and a white background as there can be a dramatic difference in the “appearance” when placed against the different backgrounds.

The value of an Opal is technically not affected by these display differences unless an unscrupulous seller was to judge the characteristics of the Opal when displayed against a black background and studio lights (as all appraisals should be conducted in ‘neutral’ conditions without enhancing elements.

DOUBLET OPALS

Australian Opal is so rare and valuable we will often cut larger Opals into ‘slices’ to allow us to make rings, pendants and earrings that are affordable.

Not everyone can afford tens of thousands of dollars for a pendant or ring. By taking a ‘slice’ (or piece) of an Opal and laying this against a background of Boulder Opal (or Black Opal) “potch” (Opal without colour) we are able to provide a completely natural piece of Opal in all of its splendor and beauty and make it affordable!

We make and distribute two types of enhanced opals, doublets and triplets. Not only do these types of opals look amazing, but they’re approximately around 1/30th the price of a black opal, making them affordable alternatives to more expensive subcategories of opal. This is because they are composed of different layers of opal and stone, rather than a ‘solid’ piece. Usually there is a thin layer of crystal opal coupled with a layer of potch (black common opal) or ironstone on the back, which acts to bring out the colour of the opal.

Triplets are similar to a doublet, with the main difference being the quartz cap on the surface of the stone that acts to magnify and enhance the colour of the opal. This results in a higher refractive index within the jewellery, usually aiding in amplifying and magnifying the various colours and patterns seen within.The addition of this ‘magnifying lens’ creates what we know as a ‘triplet’. The lens is also extremely durable and resilient, able to withstand (literally) being hit with a hammer! This feature is what makes Triplets a very popular choice for everyday wear.

As a whole, doublets and triplets exhibit incredibly vibrant tones, due to their dark backing that enhances and allows the natural beauty to leap out of the heart of the gemstone.

In order to ensure quality, we focus on the quality of materials utilised to create such a backing. We use Black Opal “potch” (which in itself can be very difficult to find). This is the material that we excavate in the mines at Lightning Ridge and cut to search for the elusive gem colour. When we find black Opal ‘nobbies’ (rocks) without colour we keep them and slice them up to use as a backing for a doublet. The Boulder Opal used to back doublets is also from the ‘darker’ end of the boulder Opal “N-Scale” and generally the harder (less porous) form of Boulder Opal. This makes an amazing base for a slice of Black, White or Crystal Opal and is tough and resilient and lasts.

Because we provide quality composition of both doublets and triplets we can guarantee our products for life against delamination. This is the process where (in inferior products) the layers of a Doublet or Triplet can be affected when they come into contact with water. Water can affect the glue, dissolving the layers and causing the Opal to turn “white”. In these situations it is not actually the Opal turning white but the glue being affected by water and dissolving!

Using silica based glues and materials with the same coefficient of expansion (ie. not plastic) we ensure that the layers will not “work apart” over time. If a manufacturer puts plastic or other cheap material on the back of a doublet or triplet (and sadly, people have done this) the jewellery will eventually undergo a process of delamination. When the Opal heats and cools plastic will expand faster than the Opal layer and cool faster also. If the glue is not silica based then the glue will also have a different rate of expansion and contraction to the layers causing the piece to ‘fall apart’ over time.

Allowing for moisture to attack and settle within the layers of the doublet, subsequently affects the colour, value, integrity and appeal of the opal itself. This is due to the fact that plastic has different coefficient of expansion to opal, meaning that it will expand and contract at a vastly different rate to that of the opal, ultimately resulting in the aforementioned delamination.

By using Boulder or Black Opal as the “base”, and the same silica-based glues used on the aerospace programs Australian Opal Cutters has created Opal DOublets and Triplets that are guaranteed for life against delamination.

If you are looking for an opal gem that has all of the characteristics of a top black opal, but at a price you can afford, then doublets and triplets are for you. A doublet is a thin layer of crystal opal with a layer of potch (black common opal SiO2·nH2O - an amorphous mineraloid comprised of hydrated silicon dioxide. (A mix of silica and water) or ironstone on the back which acts to bring out the colour of the opal).

This is the perfect gift as it an Opal an investment and the only gemstone where you can "hold a rainbow in your hand" literally! Placing a backing on a piece of Crystal Opal allows us to set Opals that would often be too fragile to allow setting. Remember that Opal often forms in microscopic fissures inside the cracks and crevices of the silica rich soil.

These Doublet Opals are hand-cut and assembled from the "rough" material by industry experts who know how to find the colour and carefully add the Opal "potch" (Opal without colour). This is an age-old tradition and is a cutting process that has not changed in 100 years. The technology behind the gluing has however changed dramatically. With modern epoxy (silica) based bonding agents our Doublets are now guaranteed for life against delamination. In the 1960’s with inferior gluing a Doublet could risk the layers separating after prolonged exposure to water. Not today! Modern silica based glues have the same coefficient of expansion as the silica in the Opal and in the Opal “potch” base. This means that when the Opal is warmed and cooled the layers all expand and contract (on a molecular level) at the same rate. This means that they will not work apart over time and are guaranteed for life!

Each Opal Doublet you will see on this site is completely natural and had not been treated or enhanced in any way, shape or form (unless specifically noted in the description).

Opal Doublets are absolutely unique as tiny microscopic water molecules actually bond and merge with silica to form a gemstone (Opal) this process is so mysterious that scientists still cannot tell us why it happens. The result is that microscopic rainbows actually form inside the gem. They are "trapped" or held there in suspension, and will not evaporate (like a rainbow in the sky does).

Opal miners have always struggled to get prices for opal that not only correlates to the stone’s true rarity, but is affordable. Throughout history large Opals (known as “Kingies”) have been incredibly valuable, but also difficult to sell. A common and simple solution that developed was to take these beautiful, priceless gemstones, and cut them into finer ‘layers’. These layers are then placed on sections of solid opal in order to contrast (and subsequently intensify) the colour. This meant that consumers could acquire adequately priced jewellery, and miners could still pay for their expensive equipment. Some might say that it is tragic to cut up the larger gems but the economics have demanded that Opal miners do this in order to survive.

However, the creation of such a technique allowed for some unscrupulous practices to form as a result. Around the 1960s and 1970s some jewellers began to use plastic as a backing for their Doublet and Triplet Opal jewellery, ultimately resulting in the pieces ‘falling apart’ over time as the two different materials reacted and shifted at different paces, causing delamination (and leading to the myth that Opal turns white over time or can lose its colour).

We don’t do this. It’s unethical and unfair to you as a buyer. We offer a lifetime guarantee against delaminating, and we have never had a customer return a doublet or a triplet; we currently utilise a NASA-developed silica-based bonding process which allows for durability and strength. Once all of the layers are bonded together with a silica-based process, the coefficient-of-expansion remains constant allowing the layers to expand and contract at the same rate. This coefficient means that the layers do not ‘work apart’ over time!

Genuine Natural Australian Gem Doublet Opal is a hydrated amorphous form of silica SiO2·nH2O consisting of spheres of silicon dioxide molecules arranged in regular, closely packed planes backed by Boulder Opal ironstone (found in remote areas in Queensland Australia). Guaranteed free of dyes and artificial colour.

Doublets and triplets are very popular due to their durability and relatively inexpensive nature. As an example, a simple triplet pendant might be sold at $1000, whereas a white opal piece with the same colour and pattern might be $4000, a crystal opal $8000, or a boulder opal with $16,000, or a Black Opal with exactly the same colour and pattern as the Triplet would be $32,000. There really is that much of a difference between a thin ‘layer’ and a solid Opal gem (even if that solid Opal gem is only a few millimetres thick)

TRIPLET OPALS

Australian Opal is so rare and valuable we will often cut larger Opals into ‘slices’ to allow us to make rings, pendants and earrings that are affordable.

Not everyone can afford tens of thousands of dollars for a pendant or ring. By taking a ‘slice’ (or piece) of an Opal and laying this against a background of Boulder Opal (or Black Opal) “potch” (Opal without colour) we are able to provide a completely natural piece of Opal in all of its splendor and beauty and make it affordable!

We make and distribute triplets. Not only do these types of opals look amazing, but they’re approximately around 1/40th the price of a black opal, making them affordable alternatives to more expensive subcategories of opal. This is because they are composed of different layers of opal and stone, rather than a ‘solid’ piece. Usually there is a thin layer of crystal opal coupled with a layer of potch (black common opal) or ironstone on the back, which acts to bring out the colour of the opal and capped with a Quartz crystal cap (for strength and color magnification).

Triplets have a quartz cap on the surface of the stone that acts to magnify and enhance the colour of the opal. This results in a higher refractive index within the jewellery, usually aiding in amplifying and magnifying the various colours and patterns seen within.The addition of this ‘magnifying lens’ creates 3 “layers” or what we know love: a ‘triplet’. The lens is also extremely durable and resilient, able to withstand (literally) being hit with a hammer! This feature is what makes Triplets a very popular choice for everyday wear.

An Australian Opal Cutters triplet is made from 100% natural materials. It contains no dyes, treatments or plastics. As all opals are different (no two are alike) it is extremely difficult to find earring pairs. Triplet earrings however take solid white and crystal Opals and slice them into fine layers. A thin slice of Opal is then carefully placed on a layer of natural Australian black Opal “potch” (Opal without colour).

This gives the Opal the same effect that a dark thundercloud has when it passes behind a rainbow. The colours (due to the black background) have a higher refractive index so the colours ‘jump’ out. On top of this is placed a layer of Quartz Crystal. Because all of the layers have the same coefficient of expansion they are guaranteed NOT to delaminate (come apart) over time. This lifetime guarantee means that you can enjoy these while swimming, bathing or washing the dishes, they are resilient, durable and beautiful. Opal triplets can be a fantastic alternative to solid stones as they are so much cheaper than solid black opals. Solid opals with the same appearance as an opal triplet can be ten times the price for exactly the same size, colour and shape!.

Triplet earrings are formed from solid white and crystal Opals that are sliced into fine layers. A thin slice of Opal is then carefully placed on a layer of natural Australian black Opal “potch” (Opal without colour). This gives the Opal the same effect that a dark thundercloud has when it passes behind a rainbow. The colours (due to the black background) have a higher refractive index so the colours ‘jump’ out. On top of this is placed a layer of Quartz Crystal. Because all of the layers have the same coefficient of expansion they are guaranteed NOT to delaminate (come apart) over time. This lifetime guarantee means that you can enjoy these while swimming, bathing or washing the dishes, they are resilient, durable and beautiful.

As a whole, triplets exhibit incredibly vibrant tones possibly the ‘brightest’ displays for any “type” of Opal. This is due to their dark backing that enhances and allows the natural beauty to leap out of the heart of the gemstone and the magnification from the quartz crystal cap.

In order to ensure quality, we focus on the quality of materials utilised to create such a backing. We use Black Opal “potch” (which in itself can be very difficult to find). This is the material that we excavate in the mines at Lightning Ridge and cut to search for the elusive gem colour. When we find black Opal ‘nobbies’ (rocks) without colour we keep them and slice them up to use as a backing for a Triplet. The Boulder Opal used to back Triplets is also from the ‘darker’ end of the boulder Opal “N-Scale” and generally the harder (less porous) form of Boulder Opal. This makes an amazing base for a slice of Black, White or Crystal Opal and is tough and resilient and lasts.

Because we provide quality composition we can guarantee our products for life against delamination. This is the process where (in inferior products) the layers of a Triplet can be affected when they come into contact with water. Water can affect the glue, dissolving the layers and causing the Opal to turn “white”. In these situations it is not actually the Opal turning white but the glue being affected by water and dissolving!

Using silica based glues and materials with the same coefficient of expansion (ie. not plastic) we ensure that the layers will not “work apart” over time. If a manufacturer puts plastic or other cheap material on the back of a triplet (and sadly, people have done this) the jewellery will eventually undergo a process of delamination. When the Opal heats and cools plastic will expand faster than the Opal layer and cool faster also. If the glue is not silica based then the glue will also have a different rate of expansion and contraction to the layers causing the piece to ‘fall apart’ over time.

Allowing for moisture to attack and settle within the layers of the Triplet, subsequently affects the colour, value, integrity and appeal of the opal itself. This is due to the fact that plastic has different coefficient of expansion to opal, meaning that it will expand and contract at a vastly different rate to that of the opal, ultimately resulting in the aforementioned delamination.

By using Boulder or Black Opal as the “base”, and the same silica-based glues used on the aerospace programs Australian Opal Cutters has manufactured Opal Triplets that are guaranteed for life against delamination.

If you are looking for an opal gem that has all of the characteristics of a top black opal, but at a price you can afford, then Triplets are for you. A Triplet is a thin layer of crystal opal with a layer of potch (black common opal SiO2·nH2O - an amorphous mineraloid comprised of hydrated silicon dioxide. (A mix of silica and water) or ironstone on the back which acts to bring out the colour of the opal).

This is the perfect gift as it an Opal an investment and the only gemstone where you can "hold a rainbow in your hand" literally! Placing a backing on a piece of Crystal Opal allows us to set Opals that would often be too fragile to allow setting. Remember that Opal often forms in microscopic fissures inside the cracks and crevices of the silica rich soil.

These Triplet Opals are hand-cut and assembled from the "rough" material by industry experts who know how to find the colour and carefully add the Opal "potch" (Opal without colour). This is an age-old tradition and is a cutting process that has not changed in 100 years. The technology behind the gluing has however changed dramatically. With modern epoxy (silica) based bonding agents our Triplets are now guaranteed for life against delamination. In the 1960’s with inferior gluing a Triplet could risk the layers separating after prolonged exposure to water. Not today! Modern silica based glues have the same coefficient of expansion as the silica in the Opal and in the Opal “potch” base. This means that when the Opal is warmed and cooled the layers all expand and contract (on a molecular level) at the same rate. This means that they will not work apart over time and are guaranteed for life!

Each Opal Triplet you will see on this site is completely natural and had not been treated or enhanced in any way, shape or form (unless specifically noted in the description).

Opal Triplets are absolutely unique as tiny microscopic water molecules actually bond and merge with silica to form a gemstone (Opal) this process is so mysterious that scientists still cannot tell us why it happens. The result is that microscopic rainbows actually form inside the gem. They are "trapped" or “held” in suspension, and will not evaporate (like a rainbow in the sky does).

Opal miners have always struggled to get prices for opal that not only correlates to the stone’s true rarity, but is affordable. Throughout history large Opals (known as “Kingies”) have been incredibly valuable, but also difficult to sell. A common and simple solution that developed was to take these beautiful, priceless gemstones, and cut them into finer ‘layers’. These layers are then placed on sections of solid opal in order to contrast (and subsequently intensify) the colour. This meant that consumers could acquire adequately priced jewellery, and miners could still pay for their expensive equipment. Some might say that it is tragic to cut up the larger gems but the economics have demanded that Opal miners do this in order to survive.

However, the creation of such a technique allowed for some unscrupulous practices to form as a result. Around the 1960s and 1970s some jewellers began to use plastic as a backing for their Triplet and Triplet Opal jewellery, ultimately resulting in the pieces ‘falling apart’ over time as the two different materials reacted and shifted at different paces, causing delamination (and leading to the myth that Opal turns white over time or can lose its colour).

We don’t do this. It’s unethical and unfair to you as a buyer. We offer a lifetime guarantee against delaminating, and we have never had a customer return a Triplet; we currently utilise a NASA-developed silica-based bonding process which allows for durability and strength. Once all of the layers are bonded together with a silica-based process, the coefficient-of-expansion remains constant allowing the layers to expand and contract at the same rate. This coefficient means that the layers do not ‘work apart’ over time!

Triplets are Genuine Natural Australian Gem Crystal Opal is a hydrated amorphous form of silica SiO2·nH2O consisting of spheres of silicon dioxide molecules arranged in regular, closely packed planes. Backed by Australian Black Opal ‘potch’ and capped with a cabochon layer of silica quartz. The three layers have the same coefficient of thermal expansion and are guaranteed for life against delamination. Guaranteed free of dyes and artificial colour.

Triplets and triplets are very popular due to their durability and relatively inexpensive nature. As an example, a simple triplet pendant might be sold at $500, whereas a white opal piece with the same colour and pattern might be $1000, a crystal opal $2000, or a boulder opal with $4,000, or a Black Opal with exactly the same colour and pattern as the Triplet would be $8,000. There really is that much of a difference between a thin ‘layer’ and a solid Opal gem (even if that solid Opal gem is only a few millimetres thick)

Search our store