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Locations: Australia, Brazil, Indonesia, Mexico, Peru, South Africa, Tanzania, Zimbabwe  Colors Found: Various  Family:  Opal  Hardness:  5.50 - 6.50  Refractive Index:  1.33 - 1.46  Relative Density:  1.80 - 2.30

One of the world’s most coveted gemstones, Opal's name evolved from the Roman word “opalus” from the Greek word “opallios” meaning “to see a change of color”. The Greek word was a modification of the ancient Indian Sanskrit name for Opal, “upala”, which meant “precious stone”. If one spoke in mixed tongues, then Opal would be opallios upala, “to see a change of color precious stone”.

While their body color covers a broad spectrum of colors, Opal’s are most prized for their unique fiery play of color and “opalescence”, which gives them the ability to reflect and refract light into flashes of multiple colors.



Historically, Opal was considered a lucky charm that brought beauty, success and happiness to its wearer. The early Greeks believed Opals embodied the powers of foresight and prophecy.

The Romans also cherished Opals, considering them to be a symbol of hope and purity - an appropriate attribute for a gem with a rainbow locked within it!

The Arabs thought that Opals must have fallen from heaven in flashes of lightning. According to Arab tradition, it is believed that Opals prevent lightening strikes, shield its wearer from any undesirable elements in their day-to-day lives and give a cloak of invisibility to its wearer when desired.

Opal featured in literature with Shakespeare referring to it in the Twelfth Night as “the queen of gems”.

The history books would have us believe that the European supplies of Opal came from India and the Middle East, but it is far more likely that they came from Hungarian mines.

Opal made the headlines in the 1890's with the first samples of Australian Opal. The Hungarians declared that the all new Australian variety was not the real thing, as Opals with such a fusion of fire and color had never been seen before.

Queen Victoria intervened in the near destruction of the 19th century Opal market when the writer Sir Walter Scott started a superstition that Opals were bad luck for people not born in October. In one of his novels, the heroine owned an Opal that burned fiery red when she was angry and turned ashen grey upon her death. Queen Victoria finally dispelled the curse by giving Opal jewelry as gifts at a royal wedding.

Scandinavian women still wear Opal hair bands to ward off the onset of grey hair and maintain their lustrous blonde locks while some people believe that this gemstone has therapeutic properties that rejuvenate the inner spirit, invigorating the mind.



Opals possess flashes of rainbow colors that change with the angle of observation called play of colour. This effect is similar to the rainbow colors displayed on a soap bubble, only much more dramatic. This should not be confused with “opalescence” (generically called “iridescence”), which is the milky blue or pearly appearance of Opal caused by the reflection of light.

The physical structure of Opal is unique. Tiny spheres of silicon dioxide form a pyramid shaped grid interspersed with water. Tiny natural faults in this grid cause the characteristic play of color.

Depending on the color of their “potch”, the host rock on which the Opal formed, Opals will either be classified as black, grey, white, fire, crystal or jelly. Opal actually exhibits many different colors including cherry colored specimens that rival Ruby, fiery-orange Opals that sparkle like Spessartite Garnet, tropical blue gems as intense as Chalcedony, and even deep gorgeous pinks.

Today 95% of the world's Opal is sourced from a handful of prominent mining areas in Australia, namely Lightening Ridge, Coober Pedy, Andamooka and Mintabe.

Black Opal

Black Opal is principally found at Lightning Ridge in New South Wales, Australia. This magnificent gemstone is the most coveted form of Opal. Its dark background color, usually black, blue, brown or grey, sets the spectral colors ablaze much like a storm cloud behind a rainbow. So prized is Black Opal that even wafer thin slices are made into doublets or triplets to give them enough strength and depth to set into gold rings and other jewelry items.

Boulder Opal

Boulder Opal is found sparsely distributed over a wide area of Australian Ironstone or boulder country where the Opal fills cracks and crevices in Ironstone boulders. Opal bearing boulder is always cut to include the host brown Ironstone. Boulder Opal is in very high demand and extremely popular. Boulder Opal is usually cut to the contours of the Opal vein creating a baroque wavy surface and is often freeform and irregular in shape, making each Boulder Opal unique.

Crystal Opal

Crystal Opal is transparent and is pure Opal (hydrated silica). It typically has a sharp clarity of diffracted color visible from within and on the surfaces of the Opal. When held out of the direct light, Crystal Opal displays some of the most intense Opal colors. This is the type of Opal used in Opal inlay jewelry which has the base of the setting blackened before a precisely cut crystal Opal is set within.

White Opal

White Opal is translucent with a creamy appearance that dominates the diffracted colors. While all the Australian Opal fields produce White Opal, the majority is mined in Coober Pedy.

Fire Opals

Fire Opals are appropriately named for their fiery cherries, sunburst yellows and deep tangerines. Unique and mysterious, Fire Opal is remarkable in that unlike many other Opals, its play of color is minimal. Also known as Mexican Opal, Mexican Fire Opal or Sun Opal, its legendary popularity instead comes from its breathtaking brilliance, opalescence, extraordinary fiery hues and stunning clarity. Fire Opals have been treasured in the Americas since the time of Aztecs, where they were named “Quetzalitzlipyollitli” or “gemstone of the bird of paradise”. Coveted by the Aztecs as symbols of intense love, such radiant gemstones were believed to have emerged from the primordial waters of creation. While Fire Opal is predominately sourced from Mexico (and occasionally Australia), this gem has recently been found in Tanzania, Ethiopia and in the West African country of Mali. A new deposit in Tanzania, aptly called African Fire Opal, displays breathtakingly intense honey hues.

Jelly Opal

Jelly Opal (also known as Water Opal) is predominately mined in Mexico. Jelly Opal offers an attractive blend of indistinct, blended colors. It is transparent with a gelatinous appearance and an occasional bluish sheen. The “opalescence” is a subtle sheen of color dancing through the gem, rather than color patches. Very occasionally it is also found in Lightning Ridge, Australia, where it is essentially Black Opal without the black potch background.

Peruvian Opal

Hailing from the Andes and coveted by the ancient Incas, Peruvian Opal is extremely rare and exhibits an exquisite translucent coloring. While it typically comes in blue or pink colors, greens are also occasionally found.

Opals From Lightning Ridge, Australia

Opals are one of Australia’s national treasures and one of the world’s most prized gemstones.

Lightning Ridge is 600 miles north of Sydney and the only place on Earth where the “King of Opals”, the Black Opal, is found.

The Black Opal mining fields of Lightning Ridge and the majority of Australia’s Opal fields are located in a geological phenomenon called ‘The Great Australian Basin’. The basin was formed from sediments of a large inland sea that existed over 140 million years ago. Approximately 120 million years later, sandstones were deposited by waterways over the top of these sedimentary rocks. Eventually these younger rocks weathered, and their silica filtered down to cavities in the older host rock in the form of a gel. The silica gel hardened forming around a nucleus, creating the Opals characteristic regular spheres and voids. It’s the diffraction of light through these transparent spaces that produce Opal’s brilliant play of colors.

Opal mining involves hard digging with picks and shovels 6-18 meters underground. Buckets are then loaded and hauled to the surface using simple mechanical winches. The rough Opal (called “nobbies”) is initially separated by hand, prior to sieving. The remaining Opal nobbies are then taken to small converted cement mixers to wash off the excess dirt.

Commenting that “the fire of the Carbuncle, the brilliant purple of the Amethyst, the sea green colors of Emerald all shining together in incredible union”, Opal clearly impressed Pliny the Elder (23-79 AD), Roman historian and author of the world’s first encyclopedia. With only a mere quarter of a percent of Opal mined making it into jewelry, if you’re looking to be impressed with Opals, there is no better place to start building your Opal collection than on GemsTV!