Opals

Global demand for typical Australian Opals is constantly growing, and since Australian Opals are non-renewable, the supply is decreasing. As a result, basic economics tells us that Australian Opals are inventively increasing in value.

According to anecdotal evidence, Boulder Opal prices have increased by up to 25% every year, while White, Crystal, and Black Opal prices have increased by 15% per year.

No one really knows how much opal is potentially hidden in the Australian Outback. What we do know is that Australian Opals are incredibly difficult to find and only occur in tiny pockets. Opal is still forming in the opal fields, and hopefully new deposits will always continue to form… but where they are hidden is the mystery! https://vimeo.com/270624714

Unfortunately, because of it’s rarity and the relentless overseas demand for opal, the local Australian customer has not had a great deal of exposure to the incredible colour and pattern of Australian Opal, but this is changing! Overseas markets are still increasing the demand because Opal is so unique, making each jewelry piece eminently collectable. But favourable publicity, and Covid meaning more Australians holidaying in Australia has encouraged more local adventurers to search for it. https://vimeo.com/270624733

Opals are rarer than diamonds in general because there are fewer high-quality opals available than there are high-quality diamonds. However, on a price per carat basis, some of the world's rarest opals, such as The Eternal Flame – the rarest opal in the world – outperform even diamonds.

Black Opal with a 'named pattern' is arguably the most commercially valuable gemstone on earth. It has been suggested that this opal is up to 5000 times rarer than diamond!  https://vimeo.com/270624733

Although the good news is on an everyday-consumer level, good quality opals are sold at reasonable prices more regularly than diamonds. But since there is no single type of opal, as there are so many types of opal and different opal fields in Australia, opal prices can range from around $10 per carat to over $10,000 per carat.

The modern birthstone for October is Tourmaline, but the traditional birthstone for October is opal. Tourmalines and opals both have their enthusiasts, but opals are far more beautiful and popular than Tourmalines.

Australia’s opal mines offer the finest variety of natural opal gemstones found. Australian Opals' intrinsic beauty and ever-changing rainbow coloured spectral play of colour make them the most valuable and highly sought-after gems in the world.

The Australian Opals fields were once an inland sea. As the centuries passed and the seas receded, very rarely some sea creatures were isolated and opalised. Eventually, the area dried out entirely and is now desert country. In time the groundwaters, holding silica solution, also evaporated with some artesian springs still active deep “underground”.

Opal is formed as water runs down through the earth, picking up silica from sandstone. 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, with a diffraction grating, this very rarely occurring array of molecules that diffracts – bends and splits – light into the colours of the spectrum in patterns that amplify the minute structure of the array.

For over 150 years, Australia has been the world's leading producer of opal. As a country, we have produced ten times the amount of opal produced by the rest of the world combined. Opal is produced in a variety of world-famous locations across the country. Australia is home to precious opal, black opal, matrix opal, boulder opal, common opal, and other rare opal forms. https://vimeo.com/205006619

As with many other gemstones, the mining of Australian Opals is fairly broad, as there are no 'block-chain' provenances in place to define an actual location.

Even though in Lightning Ridge alone there are over 200 opal mining fields, most of Australian Opal Cutters Opals come from the following mines:

Bald Hill: One of Lightning Ridge's only 'Walk-In' mines, most of the precious Opal discovered in this area was retrieved from the main workings over a 120-metre-by-30-metre area! Visitors can take self-guided or bus tours around the mine from 9 a.m. to 5 p.m. every day.

Deep-Four Mile: In the 1930s, miners discovered high-quality opal from five claims, with the deepest shaft reaching 28.5 metres.

Nebea Hill: This mine, discovered in 1973, is thought to be one of the most active in the world. Over two years, it was calculated that eight claims yielded more than $3,000,000 in Opal. Mining methods used on-site have evolved over time, beginning with large-scale open-cut mining, followed by underground mining.

New Chum and Old Chum: A 100-carat Opal stone was retrieved from this site's New Chum field, and an Opal float was discovered in the gravel on the side of the hill in the Old Chum area.

New Rush (New Nobby): This location, mined in the 1960s with a maximum shaft depth of 12 metres, yielded precious Opal, resulting in a rush to the area and the sinking of about 100 shafts.
Nine Mile: Shafts on the crest of the hill extend to 12 metres in-depth, making it one of the most worked fields still in use today. Potch was discovered in this field, interspersed with Opal.

Rouses-Six Mile: The precise location of this field is unknown, although it is understood to be near McDonald's Six Mile. In this region, only two claims yielded substantial amounts of Opal, and the majority of the Opal was in the form of large Black Nobbies.
Shallow Belars: As the name implies, this area is shallow, with depths ranging from 0.3 to 3.6 metres. This site has yielded high-quality opal, which was found in the form of opalised bivalves.

The Old Nobby: was one of the first shafts sunk in the Lightning Ridge area was at Nobbys, and Opal was discovered in the gravel at the ridge's base. Even though the rocks are particularly difficult and challenging to deal with, a significant volume of Opal has been retrieved from a lens depth of 6 metres.

The Three Mile: One of the most well-known and overworked mine, this area once housed over 1,000 workers engaged in Opal mining. Large-scale open cut mining has recently been carried out in one of the most profitable areas of the field.

The Six Mile – also known as McDonald's Six Mile – the depth ranges from 9 metres to 12 metres on the crest of the hill, with the best Opal located deeper in the earth.

Thorley's Six Mile: This area was first mined in 1902 from a depth of 6 to 12 metres, and miners rediscovered it in the 1970s, and it still produces high-quality Black Opal.

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Opals are divided into two fundamental types, Precious Opal and Common Opal. Both have different chemical formations, structures and different aesthetic appearances.

Structurally, opal is a sedimentary rock, when under the proper conditions, water percolates through the earth, becoming rich in dissolved silicates. Water deposits silicates into microscopic spheres as it enters a cavity, creating opals.

If the spheres are homogeneous in size, shape and are neatly stacked, the stone becomes a precious opal. On the other hand, the stone becomes a common opal if the spheres are randomly sized, shaped, and arranged.

Aesthetically, precious opal is an opal that shows the play of colour phenomenon caused by white light diffraction through a microstructure of neatly organised silica spheres.

Opal that does not have a play of colour is known as common opal and is usually opaque to translucent and brownish-orange in colour. However, common opals can come in any colour, some of which are quite attractive, such as red, orange, pink, green, and blue.

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A solid opal is a complete gemstone that has stayed whole through the cutting and polishing processes from a single piece of rough. Many solid opals have a natural potch or ironstone backing, which helps to highlight the inner colours of the opal.

Whereas an assembled opal – or composite opal – is a slice of natural opal that has been glued together to another silica based material, there are two types of assembled opals: doublets and triplets.

An opal doublet is made from two pieces of opal assembled together and then glued to a backing of the host rock. Typically, an opal doublet consists of a slice of high-grade precious opal cemented to a black potch on the back as this enhances the play of colour. On the side view, you can usually clearly see the very straight ‘join line’ between the two materials. Opal doublets are only a fraction of the price of a solid opal.

An opal triplet is made from thinner slices of opal, produced by sandwiching a thin layer of opal between black obsidian and a clear synthetic crystal domed cap. The clear top layer acts like a magnifying lens to enhance the appearance of the thin, precious opal layer. The second layer, black obsidian, provides a contrasting background that makes the play-of-colour in the precious layer more obvious. If you look very closely at the edge of the opal triplet, you will see a tiny line of colour that is the edge of the thin slice of precious opal. 

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Despite the growing industry of “look-alike opals”, natural opal is genuine opal that has been mined from the earth in its natural state as it comes out of the ground.

Buying rough opals is truly speculative, the risks are immense. It takes many costly mistakes to be able to determine what hides inside rough opal!

Then there are simulant opals made from non-opal materials such as plastic or glassy materials.

Sometimes called "opalite" when sold in stores, simulant opals can have a very attractive play-of-colour, an appearance that looks very similar to genuine opal and may even rival some of the best natural opals. Unfortunately, whilst they are legitimate products when sold as simulants, they are sometimes advertised or sold in ways that trick inexperienced buyers into assuming they are buying natural opal.

An untrained individual will commonly not realise that the opal is simulant. A trained gemmologist should be able to identify simulant opals from natural opals by examination with a microscope or sometimes with the unaided eye. The biggest clue that it is simulated opal is when a range of opal on display is all identical in colour and pattern. Opal does not naturally occur like that.

Your best defense against being misled into buying stimulants is to find an honest trader who has been in business for decades. ‘Cheats never prosper long term!’ They go out of business.

Most simulants on the market will quickly burn if a naked flame is held to them. Natural opal will not burn like that. A request to be allowed to do that may give some indication whether the merchant knows what he is selling, however it is not an advisable way to develop a good relationship with the merchant.

Then there is Synthetic Opal: Cultivated since 1950’s by the CSIRO a synthetic opal or lab-created opal refers to opals created by humans, although man-made it is actual opal with all the characteristics of natural opal and looking like top quality gem opal. The old adage ‘if it’s too good to be true then it is probably not true.’ If a rogue trader puts a high price on it however that can be a problem for the uninitiated. At Australian Opal Cutters we can identify it by eye as we know opal very well after 5 decades dealing in it. We are happy to help if you need help identifying any opal you have bought or considering.

Precious opals display a spectrum of colours, whereas common opal does not. The most precious opal to date has been mined in Australia as this is where the colours and patterns found are the most intense. Some common types of precious opal we sell at Australian Opal Cutters:

Pinfire Opal – also known as "Pinpoint" Opal – is opal with pinpoints of colour throughout the stone.

Boulder Opal – is formed in cavities and cracks of ironstone, usually from Queensland, Australia

Black Opal or Dark Opal – is a naturally occurring, rare and valuable solid opal formed with an Iron oxide impurity and found in Lightning Ridge, Northern NSW. This Opal has a dark body-tone colour, often black or dark grey.

Harlequin Opal – has patches of colour in the shape of rectangles or diamonds. The very rarest pattern occurring in opal.

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Common opal does not exhibit play-of-colour, instead, it is usually opaque to translucent and brownish-orange in colour. Common opals got their name because they are found in many locations and are "common" in appearance, attracting less commercial attention than precious opals.

Despite the underwhelming name, common opals are still attractive and exhibit mono colours, perfect for jewelry. Some common types of common opal we sell at Australian Opal Cutters includes:

Common Black Crystal Opal – is a Solid Black Opal, which is transparent due to little or no iron oxide on the back. Viewed from the top, it compares at least with N3 in darkness rating.

Common Crystal Opal – is a transparent/translucent opal. Sometimes mistaken for "light opal" found in Coober Pedy in South Australia.

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Fire Opals – have a colourful, transparent to translucent opal with a vivid yellow, orange, or red background colour. It may or may not exhibit "play-of-colour."

Opalised wood – is petrified wood composed of opal – rather than chalcedony or another mineral material. Opalised wood almost always consists of common opal, without play-of-colour, but a few known examples of petrified wood are made of precious opal.

Fluorescent Opal – Most opals will somewhat glow or fluoresce under an ultraviolet lamp. However, some specimens exhibit a spectacular fluorescence.

Water Opal or Hyalite – Some opal does not exhibit a "play-of-colour," does not have a base colour, and does not have a body colour like most common opals.