Opal is a unique stone as no two stones can have the same colour print. Watching the fire in an opal is enchanting.
Opal is a noncrystalline form of the mineral silica which, despite its amorphous structure, displays an amazing degree of internal organization. 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.
An opal stone is considered a "living" stone and can contain up to 30% water. They will develop crazing and lose their iridescence is allowed to dry out. It is for this reason that they are transported with a light coating of petroleum jelly to prevent them from drying out. It is important to keep it from heat and detergents that can dry the stone.
Most opal is more than 60 million years old and generally dates back to the Cretaceous period when dinosaurs roamed the earth.
It is 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 earth and slowly, over the centuries, lined the walls of cracks, vents and underground cavities in the bedrock. Most opal is found where geothermal hot springs dried up during seasonal periods of rainfall and extended dry periods.
The story of opal in Australia begins more than million years ago when the deserts of central Australia were a great 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 is 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.
Common Opal (Opal without play of colours) is very common and occurs worldwide. It is beyond the scope of this guide to list all the significant Opal occurrences. Only important deposits of Precious Opal are mentioned here.
Most Precious Opal is mined in Australia, the U.S., and Mexico. Some of the most famous Opal deposits are in Australia, and below are the most significant Australian localities:
Andamooka, South Australia
Coober Pedy, South Australia
Lightning Ridge, New South Wales
Mintabie, South Australia
White Cliffs, New South Wales
Since Queensland, Australia has numerous Opal producing areas in remote, deserted lands (sometimes hundreds of miles from the nearest community), only the names of the Opal fields are mentioned, instead of a town or village. Some of the most productive fields are Bull Creek, Hungerford, Opalton, Opalville, Quilpie and Yowah.
In Mexico, Precious Opals and Fire Opals come from several deposits. The most important are near Queretaro, in Queretaro state, and near Magdalena, in Jalisco state.
The U.S. has some of the most outstanding Opal occurrences. Virgin Valley, Humboldt Co., Nevada is rich in Opal mines producing all types of Precious Opal.
Also worthy of mention are the Spencer area Opal mines in Clark Co., Idaho; Opal Butte, Morrow Co., Oregon; and the Last Chance Opal Mine, Kern Co., California. In Canada, a notable deposit exists in Vernon, British Columbia.
Other significant worldwide Precious Opal deposits are in Ethiopia, the Czech Republic, Slovakia, Hungary, Turkey, Indonesia, Brazil, Honduras, Guatemala, and Nicaragua.
- April: Mystical Birthstone
- June: Other Birthstone
- October: Modern Birthstone
- Leo (Jul. 23-Aug. 22): Birthstone
Opal is the anniversary gemstone for the 14th and 18th years of marriage.
Opal is used to see possibilities.
Opals are very powerful in ritual magic. Since a quality opal contains every colour of every other birthstone, it can be used or charged with all the energies and powers of the other stones combined and can be used in place of any birthstone for spells, rituals or other magical needs. Opals have been linked to invisibility and astral projection. and have been used to recall past lives (each colour supposedly represents a past life).
It has reputed healing properties, especially to increase mental capacities such as creative imagination and other unused powers of the mind.
Working with gem-quality Opals
Care must be taken when polishing and setting opals. Despite their hardness, they are prone to crazing and cracking, and loss of water content causes a noticeable loss of iridescence. To prevent this, opals are normally stored in moist cotton wool or cloth until it is time to work with them. Sometimes, an opal that has lost its opalescence may be "rejuvenated" by rehydrating the stone with water or special oils, but this may only temporarily improve the stone's appearance.
In the opal cutting process the potch (a kind of mineral crust) is ground away from the presentation areas of the gem opal. This process unlike diamond mining, where the blueground (Kimberlite) is crushed away from the diamond crystals.
Individual opals are "dopped" -affixed to the ends of wooden dowels about the size of old fashioned wooden clothespins, usually with dopping wax, which resembles sealing wax.
Grinding and polishing of opals is done under a cold water drip to prevent the stones from overheating and cracking. A series of grits is used, from coarsest to finest, to produce the desired finely polished surface that reveals the full play of colour in the opal.
Most gem opals are ground to a highly polished convex oval shape called a "cabochon."
High quality opal is more valuable than diamond; up to $20,000 per carat.
There is a superstition that suggests that it is bad luck to
wear an opal if opal is not your birthstone. This superstition probably is not rooted deep in history but only goes back to the early or middle 19th Century. It may even have been an invention of Sir Walter Scott in the novel Anne of Geierstein, published in 1831. It seems that Anne had an opal that that reflected her moods: it shone red when she was angry, blue when she was sad and green when she was happy. When Anne died, the opal faded and lost all of its colour. The last observation may have actually been based on a fact: opals can deteriorate and change from a highly colourful, somewhat glassy stone to a rather colourless mass of a chalky silicon dioxide. That is because opals are unstable and are just one of the phases through which gel-like silica (SiO2) can pass on its way to becoming stable crystalline quartz..
In ancient times opal was accepted as a symbol of faithfulness and confidence.
The name "opal;" is derived from the Latin word opalus, meaning seeing jewel.
The Arabs believed that opals fell from heaven in flashes of lightning, and that's how they received their fiery colour.
Fire opals are often used in money rituals to draw funds to those who are in need, normally worn as a pendant on a gold necklace, one surrounded with 10 or 12 small diamonds is said to have excellent money drawing power.
Black opals are the tools of choice for witches and magicians, who use them primarily to enhance their magical receptive or projection powers. Black opals worn near the heart on necklaces made of gold are said to ward off evil, protect one from the evil eye and protect travelers on journeys to far away lands. Opals have been ground up and used a magic potions to heal the body, ward off bad dreams, and used an energy enhancement tools.
The white opal, when used in rituals on the full moon night, is said to bring the moon goddesses' powers to full fruition in the practitioner.
Archaeologist Louis Leakey found six thousand year old opal artifacts in a cave in Kenya!
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.
A beautiful opal called the orphanus was set in the crown of the Holy Roman Emperor. It was described "as though pure white snow flashed and sparked with the colour of bright ruddy wine, and was overcome by this radiance."
Opals are also set in the crown jewels of France. Napoleon gave Josephine a beautiful opal with brilliant red flashed called "The burning of Troy"
Opal has been described in medieval times as a cure for diseases of the eye.
Opal is given as a symbol of hope, happiness and truth.
Black opal is regarded as an extremely lucky stone.
Virgin Valley Fire Opal is a US State Gemstone of Nevada.
Starting Price is: $25 per carat $1.1