What Is Opal
What is Opal?
Australia’s Hidden Treasure – Foreword
Mysterious opals contain the wonders of the skies - sparking rainbows, fireworks, and lightning - shifting and moving in their depths.
Roman historian Pliny described the beauty of opal as the combination 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." Opal was much loved and valued highly by the Romans, who called it opalus. At the same time, opal was also sought in what would become the Americas. The Aztecs mined opal in South and Central America.
Opal was also treasured in the Middle Ages and was called ophthalmios, or eye stone, due to a widespread belief that it was beneficial to eyesight. Blonde women wore opal necklaces to protect their hair from losing its colour. Some thought the opal's effect on sight could render the wearer invisible. They were recommended for thieves! Opals are set in the crown jewels of France. Napoleon gave Josephine a beautiful opal with brilliant red flashes called "The burning of Troy," making her his Helen. Shakespeare found in the opal a symbol of shifting inconstancy, likening play of colour to play of mind in one of the most apt uses 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."
In the nineteenth century, opal was considered unlucky due to the plot of a popular Sir Walter Scott novel of the time. The heroine of the novel has her life force caught in the beautiful opal she wears in her hair and she dies when the fire in the opal is extinguished. However, Queen Victoria loved opals and often gave them as wedding presents. She and her daughters created a fashion for wearing opal. Queen Victoria was one of the first to appreciate opals from an exciting new source: Australia.
Inland 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. Mines at White Cliffs began producing in 1890.
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 lesser degree 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 sell immediately. Boulder opal is opal that has 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.
This booklet is meant as a guide, therefore we have tried to make it as non – technical as possible to increase the enjoyment to the opal enthusiast.
What is Opal?
Opal is a non-crystalline form of the mineral silica, which, despite its amorphous structure, displays an amazing degree of internal organisation. Opal is related to its more commonly found but highly crystalline cousins quartz and agate, and is formed from amorphous "balls" or lumps" of silica rather that from ordered, naturally faceted crystals. Inland 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 the silica became precious opal. Opal is one of the few gemstones that are sedimentary in origin. The water in opal is a remnant of that ancient sea.
The most striking quality of opal is its ability to refract and reflect specific wavelengths of light. 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 individual microscopic 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.
Opal Mystical Properties Opal is used to see possibilities.
Science has told us this about opal: CHEMISTRY: SiO2 . nH2O. Water usually 6 to 10% in precious opal, can be as high as 21% HEAT SENSITIVE: Varies. 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 an anchor of 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 . Japan 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.
The word evolved from the Greek word "opallus" meaning to see a change in colour. Later the latin word "opalus" came to mean precious stone. Opals stand in a class by itself. More than any other gem, each opal is distinctly an individual. No other stone has as rich and varied folklore. Opals are so unique they have their own descriptive vocabulary. They are the most delicate gems that are commonly worn. Opal's fire was long thought to be the result of iridescence. However, with the advent of scanning electron microscopes, we now know that it is a result of diffraction. source: http://www.gemsociety.org
Opal HistoryDuring the Cretaceous period (65-140 million years ago) deserts were an inland sea teeming with life. The sea gradually receded laying the foundation of silica that would form the opal of today. During the mid-tertiary period, changes in the earth’s climate caused quantities of soluble silica to be released from the sediment, finding its way down through cracks and faults, eventually hardening over time. This hardening continued to form common and precious opal. The vivid array of colour in the opal is from the uniform alignment of the silica particles. The size of the particles determines the colour as light refracts through it.Unlike many other gemstones, opal doesn’t occur in lengthy veins or concentrations. Instead, small clusters may be spread over a vast area and divided into precious or gem quality and common. Opal is found in many varieties, but precious opal represents only a small percentage of the total mined. It is estimated that between 95 and 99% of the worlds most precious opal is mined in Australia. Several unique regions of Australia specialise in different types of opal, from Coober Pedy's white and crystal opal in South Australia, through to the home of black opal, Lightning Ridge in New South Wales, up to the infamous Hayricks and Hammond's fields in northern Queensland for the boulder variety.
Resources
AUSTRALIAN SEDIMENTARY OPAL
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Last Update: 3 Jan 2011










