What Is Opal?

Australia’s Hidden Treasure

Opals contain the wonders of the skies - sparkling rainbows, fireworks and lightning. Like the sky the opal coloursshift and flash with movement, the combination of colours and patterns means every opal is unique.

Black opal was first discovered in Australia inthe late 1800s. Before its discovery the world was only aware of crystal opal which wastypicallymined in Eastern Europe. Many royal families throughout history havetreasured opal particularlyin Europe and Africa. The oldest recorded opal was found by thefamous archaeologist Louis Leakey who found six thousand year old opalartifactsin a cave in Kenya!

The Roman historian Pliny rightfullydescribed opal as the queen of gems, as opal is acombination of the beauty of all other gems: “There is in them a softer fire than the ruby, there is the brilliant purple of the amethyst, and the sea green of the emerald - all shining together in incredible union. Some by their splendour rival the colours of the painters, others the flame of burning sulphur or of fire quickened by oil.”

Opals have been popular with some of the greatest names in history including Cleopatra and Marc Anthony. One of Marc Anthony’s fellow Roman senators owned an opal stonethat reminded Marcof Cleopatra so much that he had to have it. When the Senator refused to sell it to him he sent him into exile.The French EmperorNapoleon was more successful in buyinggiving Josephine a beautiful opal with brilliant red flashes called “The burning of Troy,” making her his Helen. Opals were also famous in literature.Shakespeare likening the opalsplay of colour to play of mind in the most famous use of gemstone symbolism in literature. In Twelfth Night, he writes: “Now the melancholy God protect thee, and the tailor make thy garments of changeable taffeta, for thy mind is opal.”

For a few centuries opals seemed to disappear from history. However in modern timesQueen Victoria reignited interest in the gemstone. Queen Victorialoved opals and often gave them as wedding presents. She and her daughters created a fashion trend for thewearing opal. Queen Victoria was one of the first to appreciate opals from an exciting new source: Australia.

The story of Australian opal begins more than 100 million years ago, when the deserts of central Australia were a greatInland Sea, with silica-laden sediment deposited around its shoreline. After the sea receded and disappeared to become the great Artesian basin, weathering 30 million years ago released a lot of the silica into a solution which filled cracks in the rocks, layers in clay, and even some fossils. Some of this silica became precious opal. Opal is one of the few gemstones that are sedimentary in origin. Opal still contains 6 to 10 percent water, a remnant of that ancient sea. Gold panners in Australia found the first few pieces of precious opal in 1863.

A large percentage of the world’s stable commercial opal comes from Australia, and there are three distinctive regions where opal comes from. These are Lightning Ridge (the home of black opal) the South Australian fields Coober Pedy, Mintabie, Lambina and Andamooka (the main sources of light base opal) and the Queensland fields, where boulder opal originates.

The major opal producing fields for black opal is Lightning Ridge in New South Wales, Australia, and to a much lesserdegree Mintabie in South Australia. The most sought after black opal is red or multicolour on black, which is very difficult to find. Such stones are always cut on the fields and sold immediately.

Boulder opal is opal that is formed in a brown ironstone nodule and is distinctive because it typically presents as a thin layer of opal over a dark brown base when cut. The opal can be quite superb.

Opal from Lightning Ridge is often considered to be the best and brightest in the world.

What is Opal?

Opal is a non-crystalline form of mineral silica. Opal is related to the more common crystalline cousins such asquartz and agate. Opal differs as it is formedfrom amorphous lumps of silica rather than that from naturally faceted crystals. The chemical composition of opal is SiO2H2O, silicon dioxide combined with water (an opal stone may contain up to 30% water.) Opal’s Moh’s hardness rating is measured at 6.0 to 6.5 on the scale similar in hardness to quartz. Most opal is more than 65 million to 145 millionyears old and is found in the Cretaceous layer of rock which wasduring theperiod when dinosaurs roamed the earth. Opal tends to be found near the earth’s surface in areas where ancient geothermal hot springs once flowed. The minerals bubbled up from beneath the surface of the earthand slowly over centuries lined the walls of cavities in the bedrock.

More than 90% of the world’s quality gem opals come from Southern Australia, although it can be found in other parts of the world such as Brazil, Mexico, Czechoslovakia and Nevada. All black opal comes exclusively from Australia. The story of Australian opal begins more than 70 million years ago when the deserts of central Australia were anInland Sea. As the continent shifted the seas pulled backed and the centre of Australia became the great Artesian basin. The weathering of the basin over millions of years released silica which flowed into cracks and even some fossils forming precious opal.

The most striking feature of opal is the ability to refract and reflect specific wavelengths of colours. In fact, the term “opalescence” was coined to describe this phenomenon. The size and spacing of the amorphous spheres of silica within the stone refracts specific wavelengths of light; each sphere refracting a single, pure spectral colour much like the droplets of water in a rainbow. The interplay of these pure wavelengths of light gives opal its unique visual appeal and makes it one of the most sought-after gemstones in the world.

Birthstone Months with Opal

April: Mystical Birthstone

October: Modern and Ayurvedic Birthstone

Aquarius (Jan 20-Feb 18): Birthstone

Libra (Sep 23-Oct 22): Birthstone/Lucky Charms

Anniversary Gemstone for Opal

Opal is the Anniversary gemstone for the 14th and 18th years of marriage.

Science has told us this about opal:

CHEMISTRY: SiO2 . nH2O. Water usually 6 to 10% in precious opal, can be as high as 21% CRYSTALLOGRAPHY: Amorphous REFRACTIVE INDEX: 1.44 - 1.47 HARDNESS: 5.5 - 6.5 SPECIFIC GRAVITY: 1.99 - 2.25 CLEAVAGE: None


Opal is derived from the Latin word Upala that relates to precious stones and was considered the cupid paederos or child as beautiful as love.

Roman scholars described opal as having the green colour of emerald the brilliance of amethyst and that opal represented hope and purity which was later adopted by modern Asian countries who consider the opal as a symbolof hope.

The opal that the Romans referred to were from the present day country hungry and was crystal formed volcanic gemstones in the Carpathian mountains with flashes colour that was not seen any where else in the ancient world and really impressed the Romans

Ancient Greeks believed opal had the power to have sixth sense in foresight and also prosperity.

Cleopatra is said to have worn and opal to attract Mark Anthony.

Native Australian called aborigines’ have long history going back thousands of years and they considered opal to have spiritual properties and have many myths and legends about Opal.

They believe opal holds signs of their past ancestors and is sign of their presence and also a spirit named Muda who changes from man to pelican so pelican birds are considered spiritual also.

Asian countries had experienced opals from Indonesia and appreciate the colour spectrum of opals compared to gemstones such as ruby and sapphire which are mined in asia.

The opal has been considered as a gemstone of hope and security .

Japanese buy opals as show of wealth and standing in the community as prefer perfect formed gem quality even if opal is small.

Opal is one of the worlds most spectacular gemstone and fortunately for those born in October it is their Birthstone.

This is under the Modern Birthstone chart.

For the traditional Birthstone chart Tourmaline is considered the birthstone.

For the Mystical birthstone chart Jasper is considered the birthstone.

And for Ayurvedic Birthstone chart Opal is also considered the Birthstone.

The Ayurvedic Birthstone list is from Ayurvedic Indian Medicine - a type of medicine used for over a thousand years

Now days we use the Modern birthstone chart so Opal is now strongly associated with October birthdays.

Opal is also considered the mystical birthstone for April.

Mystical Birthstone chart is the Tibetan thousand year old version and opal in those days are more closely associated with quartz gemstones that present day opals.

Opal is considered as the gem Of the Gods

And has mystical significance and is said to help in physician vision and to open our spiritual centres.

Opal is also believed to heighten weak emotions and to strengthen memory.

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