Australia has a great wealth of opals still hidden in the more remote and forbidding parts of the continent. Unlike many other gemstones, opal does not occur in lengthy veins or in diamond-like concentrations. Small clusters of gem-quality material may be scattered over an area scores of miles in each direction; luck seems the principal reason they are found at all.
By definition, an opal is a precipitated non-crystalline variety of silica, precious varieties of which characteristically display a marked variety of changing colours that are used as gemstones, especially when cut and polished.
Opal is found in many varieties, but precious opal represents a remarkably small percentage of the total opal mined. Fine gem quality opal is more rare than rubies and emeralds. It is a more natural gem, and is a thing of beauty and obvious worth, even in its natural state.
Black opal is the most rare and valuable of all opal. It is solid and generally found as a bar (or bars) of various colours in a dark body (black, blue, brown or grey). Some black opals have a complete rainbow of colours while others have deep blue-green hues.
There are also semi-black opals and black crystal opals. While a true black opal displays sharp brilliant colours on a dark background, the semi-black opal shows a background or body colour of mid-grey. In contrast, the black crystal opal is translucent with no traces of black potch on it underside. Its colours are sharp and visible beneath the surface.
Few realise that 99.9 per cent of the world’s supply of this radiant gem is mined at only three pinpoints on the globe – Lightning Ridge, Mintabie and Andamooka. The majority of opal found at Mintabie and Andamooka is classified as semi-black opal.
Boulder opal is also classified as solid opal. It occurs as thin veins of precious opal in the cracks and cavities of light and dark brown ironstone boulders in Queensland. The opal flowed into the cracks and fissures in the boulders in liquid form millions of years ago. With the passing of centuries, the liquid material formed into solid opal and now miners cut these stones into magnificent pieces with the natural host rock left on the back.
Boulder opal can be found in many different forms and colours: its surface can be smooth or uneven, with the opal occurring as a solid piece on top of the ironstone or showing as flashing flecks of colour throughout the ironstone (known as matrix opal). Boulder opals are fashioned to standard shapes and sizes but are mostly cut in freeform shapes to highlight their individual beauty and to avoid unnecessary wastage.
Solid opals are opals that has not been backed, capped or treated by man.
A doublet opal is not a solid opal: doublets are made of thin slices of fine quality opal (generally light opal) glued to a backing piece of black potch, glass or Queensland ironstone, thus resembling natural black opal or Queensland boulder opal.
A triplet opal is not a solid opal: triplets are made of three pieces, rather like a sandwich. Firstly, a flat thin slice of precious opal is glued on to a backing of common opal, glass or porcelain that has first been darkened. A protective dome of clear quartz crystal is then cemented to the precious opal with a clear resin (glue) to complete the triplet opal. A doublet opal is more valuable than a triplet because it has a greater opal content.
The Australian opal fields were at one time under the sea, so opalised fossils are occasionally unearthed. As the ages passed and the seas began to recede, millions of sea creatures were isolated and marooned. Eventually the area dried completely and the inland is now a dry desert country.
In time the ground waters, holding silica solution, also evaporated. They left behind the phenomenon known as ‘opal’. Hydrated silica was deposited in fissures in sandstone, or gypsum, and on jasper. It entered the shells of the stranded marine creatures. In some cases it even replaced the entire shell.
One can find opalised wood, prehistoric animal bones, sea creatures, full sea shells, skin shells, sponges, fish skeletons and even opalised stems of plants on the opal fields.
Potch is the common non-precious opal exhibiting no play of colour.
If interested in purchasing any of the Lighting Ridge or Boulder opal pendants shown here, please contact us by leaving us a comment below so we can get back to you with for more information. Pendants, earrings and bracelets are available at wholesale prices. Note that each piece is made with fine quality silver and is an individual piece designed by a local jeweler who also mines and polishes the opals. Some pieces shown here may not be available at the time of inquiry. However, other pieces will be. We are Australia based.
To see what opals look like close up, see the next post: here
Opal Fields in Australia
Australia is the world’s greatest producer of precious opal. Over 90 per cent of the world’s commercial opal comes from the desolate outback. All of the significant opal deposits in Australia are located within the Great Artesian Basin or close to it. The places where opal has been mined over the past 100 years are located here. The most important deposits are found in New South Wales, South Australia and Queensland.
Today, the mining is carried out at the following main areas and each produce solid opal with specific characteristics and colour patterns: Lightning Ridge, NSW; White Cliffs, NSW; Central Queensland; Cooper Peddy S.A; Mintabie, SA and Andamooka, SA. The opals I have sourced come from Lightning Ridge, NSW and Central Queensland. They are mined, polished and set into jewellery (Fine Silver/ Gold) by local residents in Far Northern NSW.
Lightning Ridge, NSW
This is a town famous for its rich, rare and glorious black opal. Black opal derives its name from the colour of the ‘nobbies’ or pieces of rough opal in which the gems are usually found. Lightning Ridge is located 770 kilometres northwest of Sydney in an area that also produces wheat, sheep, cattle and oilseeds.
Black opal was first discovered at Lighting Ridge in the late 1880s however, its commercial value was not at first recognised by buyers. Mining actually commenced in the early 1900s when some opal nobbies were found and trial shafts erected.
Opal occurs at Lightning Ridge either as ‘nobbies’, or in seams and thin layers within vertical or horizontal joint plains, in a soft greyish claystone that hardens and whitens on drying. This claystone is commonly referred to as ‘opal dirt’. The opal dirt levels occur between 6 and 18 metres from the surface, but have been known to go as deep as 30 metres.
The fields also yield opalised shells, wood, and reptilian bones of the Cretaceous age.
Some of the traditional fields around Lightning Ridge include the Three Mile and Thorleys Six Mile however, most opal is now being found in newer areas away from the township.
The history of opal in Queensland dates back to the early 1870s, but it wasn’t until 1889 when the gem was successfully marketed that the industry became established. The discovery of opal was reported in many areas however, the real development of Queensland’s vast opal deposits began in 1873 with the discovery of fine quality opal north of Thargomindah. Within two years there had been many exciting finds throughout south western Queensland however, during those early years production was low because there was no ready market for the gem. It took the tireless efforts and sheer determination of a young entrepreneur named Tully Wollaston to convince world gem merchants to accept Queensland opal that the industry was finally established.
Today, the Queensland opal belt covers an extensive area in the southwest of the state that is around 1000 kilometres long by 300 kilometres wide. There are local areas throughout the region where opal mines are concentrated, such as Yowah, Quilpie, Eromanga and Jundah.
HISTORY OF OPALS
The history of Australian opals started as late as 1849 at a cattle station called Tarrawilla, near Angaston some 80km outside Adelaide however, Australian opal did not appear on the world market until the 1890s. Prior to the emergence of Australian opal on the market, opal was sourced in Hungary and South America. Consequently, the Hungarian mines promoted the idea that Australian opal was not genuine, probably because gems with such brilliant colour had not been seen before.
Throughout history, opal has been regarded as a stone of good fortune. In ancient times, precious opal was included among the noble gems; it was believed that the gem possessed magical properties.
The Romans established opal as a precious gemstone, obtaining their supplies from traders in the Middle East. They believed the opal was a combination of the beauty of all precious stones. They ranked opal second only to emeralds, and carried opal as a good luck charm or talisman because it was believed that like the rainbow, opal brought its owner good fortune. In the days when Rome spread her legions across Europe and Africa, a Roman Senator by the name of Nonius opted for exile rather than sell his valuable opal to Marc Antony who wanted to give it to his famous lover Cleopatra.
Eastern peoples also dealt very heavily in this precious stone, which was believed to bring luck and to enhance psychic abilities.
During the late 18th and 19th centuries opal fell out of favour, as it was associated with pestilence, famine and the fall of monarchies.
During the decimation of Europe by the Black Death, it was rumoured that an opal worn by a patient was aflame with colour right up to the point of death, and then lost its brilliance after the wearer died. The superstitious thought the opal had some bearing on the victim’s destiny. However, it did not occur to them that the changes in the appearance of the opal was due to the drastic rise and fall of the patient’s temperature during their fever and subsequent death.
In a tale of ill luck related to a monarchy, it is told that in the 19th century, King Alfonso XII of Spain had received an opal ring from a vengeful Comtesse he had previously courted. The King presented the ring to his wife, who had greatly admired it, and shortly thereafter she died mysteriously. A succession of wearers in the royal family followed the Queen’s untimely end. Finally, the King then placed the opal ring on his own finger and in a little time his life also ended. However, it must be pointed out that during this time cholera was raging throughout Spain-over 100,000 people died of it and it attacked all classes. The reputation of the opal as a charm against cholera must have been known to the King, who used a talisman that acted fatally instead of beneficially.
Centuries later, Shakespeare referred to opal as “a miracle” and the “Queen of Gems”. Elizabethans prized opal as highly as the diamond for its brilliant colours and flashes of fire. Indeed, opal was a lucky stone.
Another anecdote tells the tale of a rich city financier who took his ‘opal ring’ to a jeweller: he wanted to sell it because of the ill luck it had brought him. A tale of misfortune was recounted. As a result of wearing the ring, his wife had fallen ill, a condition that also affected his son, and he encountered among many other troubles financial difficulties and ill health. The jeweller, however, merely smiled and showed him that the stone in the ring was not an opal but a moonstone. Only his imagination had endowed the opal ring with such unpleasant properties.
Nevertheless, opal has found a place in the crowns of Kings: fine specimens of opal were included in the crown jewels of France, and the Holy Roman Emperor’s crown contained an opal stone. Queen Victoria adored opal and wore many throughout her reign. Today, many royals and heads of state own and wear fine quality gem opals.