Opal:
Basic facts:
Month stone: October
Origin: Australia, Brazil, Ethiopia, Mexico, Peru, South Africa, Sudan, Tanzania & Zimbabwe
Colors: Various
Family: Opal: SiO2 + H2O
Hardness: 5.5 - 6.5
Refractive Index: 1.37 – 1.52
Specific Gravity: 1.98 – 2.50
Treatment: Can be treated
One of the world's most sought-after gemstones, opal whose name evolved from the Roman opalus derived from the Greek 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."
Myths and legends
Historically, opal has been a good luck charm that brought beauty, success and luck to the wearer. The early Greeks believed opals embodied foresight and prophecy.
The Romans also loved opals and believed they were a symbol of hope and purity. The Arabs believed that opals must have fallen from the sky in lightning bolts. According to Arabic tradition, opals are believed to prevent lightning strikes, protect its wearer from all unwanted elements in their day to day lives and provide a cloak of invisibility to the wearer when desired.
Opal made headlines in the 1890s with the first specimens of Australian opal. The Hungarians declared that the new Australian variety was not genuine because opals with such a fusion of fire and color had never been seen before. According to Koori (Aboriginal) legend, the creator came down to earth on a rainbow to bring a message of peace to all people. At the point where his feet touched the ground, the stones became alive and began to sparkle in all the colors of the rainbow, giving rise to Australian opals. Today, opals are one of Australia's national treasures and one of the world's most valuable gemstones.
Scandinavian women still wear opal hair bands to ward off the appearance of gray hair, while some people believe that this gemstone has therapeutic properties that rejuvenate the spirit and strengthen the mind.
Opal facts
Opals have a rainbow-like luster that changes with the angle you look at the stone - called play of color. This effect is similar to the rainbow colors that appear on a soap bubble, only much more dramatic. This should not be confused with opalescence, which is the milky blue or pearl appearance of opal caused by scattering of light.
The physical structure of opal is unique. Small precipitated spheres of silica form a pyramidal lattice interspersed with water. Small natural faults in this mesh cause the characteristic play of colors.
Opals are usually classified according to the "potch" (the base stone, also called "matrix") on which the opal is formed. For example, black opal has a black potch, a semi black opal a potch darker than gray, but not quite black, a white opal a white potch.
Opal actually exhibits many different colors including cherry-colored specimens that match the best rubies, fiery-orange opals that sparkle like mandarin garnet, tropical blue stones as intense as chalcedony, and even beautiful pinks and greens.
Today, about 95% of the world's opals come from a handful of prominent mining areas in Australia, namely Lightning Ridge, Coober Pedy, Andamooka and Mintabie.
Black Opal
Black opal is found mainly at Lightning Ridge in New South Wales, Australia. Known as the "King of Opals," Lightning Ridge black opal has been sought after since its discovery in 1902. About 90 miles north of Sydney is Lightning Ridge (a town of about 15,000 people) which is the world's largest source of the finest black opals.
This magnificent gemstone is the most sought after form of opal. Its dark background color sets spectral colors on fire much like a storm cloud behind a rainbow (the black background provides contrast and intensity to this opal's color spectacle). So valued is black opal that even very thin slices are made into duplicates or triplets to give them enough strength and depth to be included in gold rings and other jewelry.
The black opal mining within the Lightning Ridge and the majority of Australia's opal fields lie in a geological phenomenon known as the Great Australian Basin. The basin was formed from the sediments of a large inland sea that existed over 140 million years ago. About 120 million years later, sandstones have been deposited by watercourses over the top of these sedimentary rocks. Their silica is filtered down to cavities in the older bedrock in the form of a gel. The silica hardened and formed around a nucleus, creating the opal's characteristic regular spheres and cavities. It is the diffraction of light through these transparent surfaces that produces the opal brilliant play of color.
Unfortunately, all Australian opals are becoming increasingly rare, especially those from Lightning Ridge. The old fields on Lightning Ridge that yielded large cabochon stones are nearly exhausted, with only marginal areas currently being worked. Although the government has opened many new prospective areas, there have been no significant new deposits to date. Opal production at Lightning Ridge is half of what it was ten years ago.
Boulder Opal
Boulder opal is found sparsely distributed over a large area of Australian ironstone or boulder country where opal (silica mix) fills veins, cracks, cavities and fissures in ironstone boulders. Opal boulder stone is always ground to include the brown host stone. One of the largest boulder opal areas is located northwest of Lightning Ridge in western Queensland. The Queensland Boulder Opal areas comprise a large area centered on the town of Quilpie and extend as far north as Winton and south to Cunamulla.
Known for its vivid flaming clear rich colors, this variety is in very high demand and very popular. Interest in Queensland Boulder Opal has increased significantly over the past 20 years.
Fire Opal
Fire opals are aptly named for their fiery cherries, yellow tans and deep tangerines. Unique and mysterious, fire opal is remarkable in that, unlike many other opals, its color play is minimal. Also known as Mexican opal, Mexican fire opal, Tanzanian fire opal, cherry fire opal, Ethiopian fire opal, Brazilian fire opal or sun opal, the legendary popularity of the place comes from its breathtaking brilliance, opalescence, extraordinary fiery hues and amazing clarity.
Fire opals have been highly valued in America and the Aztec Indians called this stone Quetzalitzlipyollitili or ;gemstone of the bird of paradise;. For the Aztec Indians, the fire opal was a strong symbol of love and lust. While fire opal is mainly found in Mexico (and sometimes Australia), this gemstone has recently been found in Tanzania, Ethiopia, Mali and now Brazil. While opal has been mined in Brazil since about 1945, production has always been very limited, making it difficult to secure commercial quantities. Today the Piaui state is increasingly internationally recognized for its opals with their quality comparing favorably with all the finest Australian opals.
Green Opal
Discovered in the 1960s, green opal is a green translucent opal that resembles chrysoprase or jade and is commonly called PRASEM opal or chrysopal due to its resemblance to chrysoprase. It is mined in the Arusha region of Tanzania (the same region as tanzanite). Although this gemstone does not show the same color play found in some opals, its mint to apple green color has made it a very popular opal for jewelry. Trace amounts of nickel give this opal its unique color.
Jelly Opal
Jelly opal (also known as water opal or crystal opal) is mined in Mexico and Australia. Offering an attractive mix of indistinct colors, it is a transparent pure opal with a gelatinous appearance and sometimes pronounced opalescence (bluish sheen). The play of color is a subtle luster that dances across the entire stone rather than distinct color fields. When held in direct light, a jelly opal can display some of the most intense opal colors.
Peruvian Opal
It comes from the Andes and was appreciated by the ancient Inca Indians. Peruvian opal is extremely rare and exhibits an exquisite translucent color. Although normally found in blue or pink colors (also sometimes green).
Semi Black Opal
With a lighter transparency than black opal, semi black opal has a color darker than black, but not quite black. Opacity is the key that differentiates black from semi black with black opal appearing more opaque than semi black opal. Semi black opal was discovered at Andamooka in the 1930s. Located 40 miles north by road from Adelaide, South Australia, Andamooka is a typical dusty "Wild West" desert town. While Andamooka opals are still world famous, only a small amount of opal is mined from Andamooka due to high logistical costs due to its remoteness. Andamooka opal is typically of exceptionally high quality, but has become more difficult to purchase in recent years.
White Opal
White opal is transparent with a creamy appearance that dominates broken colors. While all of the Australian opal fields produce white opal, the majority is found in Coober Pedy.
Basic facts:
Month stone: October
Origin: Australia, Brazil, Ethiopia, Mexico, Peru, South Africa, Sudan, Tanzania & Zimbabwe
Colors: Various
Family: Opal: SiO2 + H2O
Hardness: 5.5 - 6.5
Refractive Index: 1.37 – 1.52
Specific Gravity: 1.98 – 2.50
Treatment: Can be treated
One of the world's most sought-after gemstones, opal whose name evolved from the Roman opalus derived from the Greek 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."
Myths and legends
Historically, opal has been a good luck charm that brought beauty, success and luck to the wearer. The early Greeks believed opals embodied foresight and prophecy.
The Romans also loved opals and believed they were a symbol of hope and purity. The Arabs believed that opals must have fallen from the sky in lightning bolts. According to Arabic tradition, opals are believed to prevent lightning strikes, protect its wearer from all unwanted elements in their day to day lives and provide a cloak of invisibility to the wearer when desired.
Opal made headlines in the 1890s with the first specimens of Australian opal. The Hungarians declared that the new Australian variety was not genuine because opals with such a fusion of fire and color had never been seen before. According to Koori (Aboriginal) legend, the creator came down to earth on a rainbow to bring a message of peace to all people. At the point where his feet touched the ground, the stones became alive and began to sparkle in all the colors of the rainbow, giving rise to Australian opals. Today, opals are one of Australia's national treasures and one of the world's most valuable gemstones.
Scandinavian women still wear opal hair bands to ward off the appearance of gray hair, while some people believe that this gemstone has therapeutic properties that rejuvenate the spirit and strengthen the mind.
Opal facts
Opals have a rainbow-like luster that changes with the angle you look at the stone - called play of color. This effect is similar to the rainbow colors that appear on a soap bubble, only much more dramatic. This should not be confused with opalescence, which is the milky blue or pearl appearance of opal caused by scattering of light.
The physical structure of opal is unique. Small precipitated spheres of silica form a pyramidal lattice interspersed with water. Small natural faults in this mesh cause the characteristic play of colors.
Opals are usually classified according to the "potch" (the base stone, also called "matrix") on which the opal is formed. For example, black opal has a black potch, a semi black opal a potch darker than gray, but not quite black, a white opal a white potch.
Opal actually exhibits many different colors including cherry-colored specimens that match the best rubies, fiery-orange opals that sparkle like mandarin garnet, tropical blue stones as intense as chalcedony, and even beautiful pinks and greens.
Today, about 95% of the world's opals come from a handful of prominent mining areas in Australia, namely Lightning Ridge, Coober Pedy, Andamooka and Mintabie.
Black Opal
Black opal is found mainly at Lightning Ridge in New South Wales, Australia. Known as the "King of Opals," Lightning Ridge black opal has been sought after since its discovery in 1902. About 90 miles north of Sydney is Lightning Ridge (a town of about 15,000 people) which is the world's largest source of the finest black opals.
This magnificent gemstone is the most sought after form of opal. Its dark background color sets spectral colors on fire much like a storm cloud behind a rainbow (the black background provides contrast and intensity to this opal's color spectacle). So valued is black opal that even very thin slices are made into duplicates or triplets to give them enough strength and depth to be included in gold rings and other jewelry.
The black opal mining within the Lightning Ridge and the majority of Australia's opal fields lie in a geological phenomenon known as the Great Australian Basin. The basin was formed from the sediments of a large inland sea that existed over 140 million years ago. About 120 million years later, sandstones have been deposited by watercourses over the top of these sedimentary rocks. Their silica is filtered down to cavities in the older bedrock in the form of a gel. The silica hardened and formed around a nucleus, creating the opal's characteristic regular spheres and cavities. It is the diffraction of light through these transparent surfaces that produces the opal brilliant play of color.
Unfortunately, all Australian opals are becoming increasingly rare, especially those from Lightning Ridge. The old fields on Lightning Ridge that yielded large cabochon stones are nearly exhausted, with only marginal areas currently being worked. Although the government has opened many new prospective areas, there have been no significant new deposits to date. Opal production at Lightning Ridge is half of what it was ten years ago.
Boulder Opal
Boulder opal is found sparsely distributed over a large area of Australian ironstone or boulder country where opal (silica mix) fills veins, cracks, cavities and fissures in ironstone boulders. Opal boulder stone is always ground to include the brown host stone. One of the largest boulder opal areas is located northwest of Lightning Ridge in western Queensland. The Queensland Boulder Opal areas comprise a large area centered on the town of Quilpie and extend as far north as Winton and south to Cunamulla.
Known for its vivid flaming clear rich colors, this variety is in very high demand and very popular. Interest in Queensland Boulder Opal has increased significantly over the past 20 years.
Fire Opal
Fire opals are aptly named for their fiery cherries, yellow tans and deep tangerines. Unique and mysterious, fire opal is remarkable in that, unlike many other opals, its color play is minimal. Also known as Mexican opal, Mexican fire opal, Tanzanian fire opal, cherry fire opal, Ethiopian fire opal, Brazilian fire opal or sun opal, the legendary popularity of the place comes from its breathtaking brilliance, opalescence, extraordinary fiery hues and amazing clarity.
Fire opals have been highly valued in America and the Aztec Indians called this stone Quetzalitzlipyollitili or ;gemstone of the bird of paradise;. For the Aztec Indians, the fire opal was a strong symbol of love and lust. While fire opal is mainly found in Mexico (and sometimes Australia), this gemstone has recently been found in Tanzania, Ethiopia, Mali and now Brazil. While opal has been mined in Brazil since about 1945, production has always been very limited, making it difficult to secure commercial quantities. Today the Piaui state is increasingly internationally recognized for its opals with their quality comparing favorably with all the finest Australian opals.
Green Opal
Discovered in the 1960s, green opal is a green translucent opal that resembles chrysoprase or jade and is commonly called PRASEM opal or chrysopal due to its resemblance to chrysoprase. It is mined in the Arusha region of Tanzania (the same region as tanzanite). Although this gemstone does not show the same color play found in some opals, its mint to apple green color has made it a very popular opal for jewelry. Trace amounts of nickel give this opal its unique color.
Jelly Opal
Jelly opal (also known as water opal or crystal opal) is mined in Mexico and Australia. Offering an attractive mix of indistinct colors, it is a transparent pure opal with a gelatinous appearance and sometimes pronounced opalescence (bluish sheen). The play of color is a subtle luster that dances across the entire stone rather than distinct color fields. When held in direct light, a jelly opal can display some of the most intense opal colors.
Peruvian Opal
It comes from the Andes and was appreciated by the ancient Inca Indians. Peruvian opal is extremely rare and exhibits an exquisite translucent color. Although normally found in blue or pink colors (also sometimes green).
Semi Black Opal
With a lighter transparency than black opal, semi black opal has a color darker than black, but not quite black. Opacity is the key that differentiates black from semi black with black opal appearing more opaque than semi black opal. Semi black opal was discovered at Andamooka in the 1930s. Located 40 miles north by road from Adelaide, South Australia, Andamooka is a typical dusty "Wild West" desert town. While Andamooka opals are still world famous, only a small amount of opal is mined from Andamooka due to high logistical costs due to its remoteness. Andamooka opal is typically of exceptionally high quality, but has become more difficult to purchase in recent years.
White Opal
White opal is transparent with a creamy appearance that dominates broken colors. While all of the Australian opal fields produce white opal, the majority is found in Coober Pedy.