Opal Types & Care

Updated: Jul 16, 2021

Australia mines 97% of the world's different types of Opals. These include the stunning Black Opals, Boulder Opals, White Opals, Crystal Opals, and Opal Doublets and Triplets. These are made into beautiful varieties of opal rings, opal earrings, opal pendants and necklaces. 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'.


**^ 2.59 ct black opal gem 11.5x9x3mm $6,000.00*


Australian Black Opal from Lightning Ridge N.S.W. is the most famous form of Opal in Australia. Named Lightning Ridge because in a terrible storm a farmer, his dog, and 600 sheep were all killed by lightning. Black Opals with Gem colour and a "named" pattern are 5000x rarer than diamond.

Indigenous Aboriginal Elders from the Yolgnu tribe 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, hiding 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 the Australian Opal is literally a rainbow that has been transformed into a gemstone. The water in the silica is stationary rather than moving.

The colour bar or the 'play of colour' 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.


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 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 form in cracks and fissures in these boulders.

^14ct Australian Opal. GIA Certified.Loose large natural Australian solid White Crystal Opal. 20.62 x 16.12 x 6.78 mm.



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 all year round. The cool underground mines have become popular as living quarters, and now most of the locals live underground!



Where do I find Crystal Opal?

Most Opal fields across the world produce some type of Crystal Opal, as it is formed with no base (like potch, ironstone or sandstone). It is appreciated by many for its rarity and unique colour patterns. The most well famous mines of Crystal Opal are -

  • Coober Pedy, South Australia, Australia

  • Mintabie, South Australia, Australia

  • Lightning Ridge, New South Wales, Australia

  • Andamooka, South Australia, Australia

  • Welo, Ethiopia

The back of a Crystal Opal may be enhanced to increase its brightness, but these must be labeled “solid enhanced Crystal Opals” otherwise known as Opal doublets.

In Australia the most expensive type of Crystal Opal is the Black Crystal Opal from Lightning Ridge, Queensland, Australia. They have some of the most amazing unique patterns and are well sought after by Opal collectors.This particular Crystal Opal is formed on black potch but still with transparent body. The Opal is considered to have a dark body tone.

Ethiopian Crystal Opal

Ethiopian Crystal Opal is mined in the Ethiopian Opal fields of Welo and has spectacular patterns from Honeycomb to patchwork and snake skin and is sometimes referred to as Ethiopian Fire Opal.

Ethiopian Crystal Opal is also found at Yita Ridge in the Menz Gishe District of Shewa Province, around 150 miles northeast of Addis Ababa, the capital of Ethiopia. The patterns and colours found in Ethiopian Crystal Opals are out of this world.

HOW TO CARE FOR OPALSFAQ : How do I take care of opals? What is the best way of caring for opal? What is a doublet? What is a triplet? How do I clean my opal? What happens if I get my opal wet? Because I love opal, I like to educate our customers on how best to care for their opals, so they can enjoy the beauty of this individual and precious gemstone for many many years to come. Please take a few moments to read this guide, and don’t hesitate to email us if you have any questions.

DOUBLETS, TRIPLETS, & SOLID OPAL Taking care of opal is easy. All it takes is a little bit of common sense and knowledge about opal. Before deciding how to best care for your opal you need to be aware of the type of opal you have;

  • Solid Opal – Natural solid opal which has only been cut and polished.

  • Doublets – Doublet opals consist of two layers, a thin slice of opal and a black backing. The slice of opal is cemented to the backing in order to enhance the colour.

  • Triplets – Similar to doublets, triplets also include a third transparent layer on the top (quartz or glass) to protect the opal and give it a rounder shape.

**note at Halestone I only use Solid or doublet opals.


Opal Doublet as the name suggests, is a thin layer of precious Opal cemented onto a backing, usually a piece of common Black Opal or Ironstone. They were originally created from Opal that was perhaps too thin to produce a solid stone. Opal doublets are a cheap and inexpensive way to buy a colorful piece of precious Opal without the cost of a solid Opal. Some of the patterns and the brightness of the Opal doublets is incredible.


Solid Opals – Opal is a soft stone, approximately the same hardness as glass (around 6.5 on Moh’s hardness scale), so it is important to treat your opal carefully in order to avoid damaging it. Remove your opal jewellery if there is a chance it will be scratched or broken (i.e. working in the garden, moving furniture, etc.) Many people believe solid opals can be damaged by water – however, this only applies to doublets and triplets. Solid opals are fine in water. In fact, most precious opals contain about 5-6% water. As a result, opal may crack if subjected to very dry conditions or rapid changes in temperature. Try to avoid very high temperatures or low humidity extremes, such as boiling water or zero humidity bank vaults. Doublets & Triplets – Caring for doublets or triplets is a little different to caring for solid opals. Because doublets and triplets consist of multiple layers glued together, prolonged exposure to water will eventually cause lifting between the layers and the infiltration of water. A doublet or triplet will take on a ‘foggy’ or grey appearance if this happens. This does not mean your opal will be ruined if you wear it in the shower once, or are caught in the rain. It takes prolonged exposure to cause water damage to a doublet or triplet.

Professional polishing can bring new life to an opal which has become dull or scratched.

STORING SOLID OPALS If you need to store your opal away for a period of time, simply place it in a padded cloth bag for protection and store it away. For longer storage periods, place your opal in cotton wool with a few drops of water, then into a sealed plastic bag just to be safe. The water is not intended to soak into the stone (Australian opal is impervious) but will prevent water coming out of the stone if it is exposed to very low humidity environments (for example, zero humidity storage safes).


Over many years there has been guidelines developed on how to value Opal. We are going to explore the 10 factors that contribute to an Opals final value. These factors are:

  1. Color

  2. Direction / Play Of Color

  3. Pattern

  4. Body tone

  5. Brightness

  6. Shape

  7. Inclusions

  8. Which Opal Field

  9. Natural vs Treated

  10. Country Origin

So there ya go.

Note: Halestone Uses carefully selected Australian Solid Black/Boulder/Crystal Opals and Doublet Opals and more specific information is listed in the item description. <3 Amy

5 views0 comments