Australian opal

Magic beauty found in dusty places

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Opal is one of the most wonderful gemstones. Did you know that Australian opal makes up approximately 95 % of the world's precious opal? Yes, Australia is a classical opal country.
In 1994 opal was declared to be Australia's national gemstone..

Look at an opal stone from different angles - it changes it colours. The beauty of opals, the play of colours, has fascinated people for centuries.

Do you have questions about Australian opal? Find the answers in the Outback Guide's opal section!

• What is opal? How does it form?
• Where is opal found in the Australian Outback?
• The different types of opal.
• What are doublets and triplets?

Opal basics

In simple terms, opal is a mix of silica and water. Scientifically, opal is amorphous silica (SiO2.nH2O) which is solidified from liquid silica.
As you can imagine, the synthesis of opal was an ancient process. The opal building started about 15 - 30 million years ago. Silica gel seeped through sedimentary layers until it was stopped by a clay level. Australian opal therefore is called sedimentary opal. Over million of years, the liquid Silica gel hardened to form the opal deposit of the artesian basin, the ancient underground water reservoir of the eastern Outback.
Australia's precious opals contain around 5 -6 % water.

Generally, opal comes in two forms

• precious opal - valuable gemstones with the characteristic play of colours.
• common opal or potch - that is one-coloured opal.

Precious opal has the most value, as the name says. It is the amazing play of colours we all love. The colours of the spectrum displayed in precious opal result from interference and diffraction of light when it passes the silicea spheres in the opal's structure.

Precious opal comes in different types. It can be white opal, crystal opal, black opal, or boulder opal. Only about 0.25 % of opal mined in Australia is considered precious opal. However, 95 % of the world's precious opal is found in Australia!

It is not easy to make a fortune in the opal fields, but some people do.

Australia's opal mining fields

Opal is mined in South Australia, Queensland and New South Wales. A trip to the opal mining fields in whatever state is a wonderful journey into the Australian Outback.

The most famous opal mining towns are Coober Pedy and Andamooka in South Australia. White Cliffs and Lightning Ridge are in New South Wales. The latter is well-known for its black opal. Central Queensland is the home of boulder opal, found in Quilpie, Yowah and Winton.

Opal mining towns are unique places to visit. Rough and dusty, with colourful characters. Molehills of stones from the mines and huge machinery are the first signs you'll notice when you approach an opal town. But hey, you'll love them!

Despite the rough appearance, you'll find full services in most towns. Coober Pedy hotels even offer the unique experience to sleep underground. And don't forget the opal shops where you can see (and buy) beautiful opal jewellery.

When is the best time to visit the opal fields?

April to late September is the best time for a trip to the opal fields. It is getting "bloody" hot in summer out there. The Australian climate page gives you an idea about when to visit the Australian Outback.

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