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The Directors Gift Selection
Opal Information
The play of color, or fire, prized so highly in
precious opal, is a special effect of light. All color comes from light, which
may be absorbed or reflected back from solid substances like gemstones. The
absorbed colors, "bouncing" around the silica spheres and the spaces
between them, produce a brilliant play of color as light moves across an opal's
surface.
 Each type of color is named according to its appearance. Large square-shaped
patches of color are called harlequin or mosaic. Flash fire describes large
irregular patches of color. Flame fire is streaks of color, while pin fire
refers to small pinpoints of color. Sheets of color that roll across the surface
as the stone is moved are called rolling fire. Broad flash fire is sheets of
color that cover the stone. Other descriptive names include zebra, Chinese
writing, and straw. These latter varieties are rarely found.
Color descriptions in opal usually refer to the background, or base, color.
That's the color seen when looking straight down at the opal. Although opal is
found in a variety of colors, including yellow and blue, black is most highly
prized base color. Additionally, opals may range from transparent to opaque.
Their names indicate the opals color and translucency. A black opal is opaque,
with the play of color showing against a dark background. Black crystal opal is
the same as black opal, except it is transparent or translucent. White opals
displays its play of color against an opaque white background.
The name opal may also pre roman times originally have come from upala, which is
Sanskrit for stone. Opal has been valued since ancient times, its first use
being to protect the wearer from diseases, particularly those of the eye. Opals
were especially popular in the Middle Ages, when it was thought to make a person
invisible.
Opal is unique among gemstones. Made of water, but filled with fire. With its
brilliant beauty, the fiery opal enchants with its dazzling display of color.
Its special place in the human heart is secure.
Opal: Nature's Fireworks
Mysterious opals contain the wonders of the skies - sparking rainbows,
fireworks, and lightning - shifting and moving in their depths. Opal has been
treasured throughout history around the world. Archaeologist Louis Leakey found
six-thousand year old opal artifacts in a cave in Kenya!
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 splendor rival the
colors 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 color. Some
thought the opal's effect on sight could render the wearer invisible. They were
recommended for thieves!
Opal as Muse
A beautiful opal called the orphanus was set in the crown of the Holy Roman
Emperor. It was described as follows: "as though pure white snow flashed
and sparkled with the color of bright ruddy wine, and was overcome by this
radiance." This opal was said to guard the regal honor.
Opals are also 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
color 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.
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.
Ancient opal came from the mines near Cervenica, Hungary, in what is now Eastern
Slovakia, where hundreds of men mined the stone. Ancient opal fanciers never had
the chance to see the opal of Australia, where the opal of today was born, which
far surpasses the beauty of Hungarian opal in fire and brilliance.
A Gem of Water, Born in the Desert
The story of opal in Australia begins more than 100 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 this silica became precious opal. Opal is one of the
few gemstones that is 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.
Only opal with a perfectly aligned grid of silica spheres will show play of
color, which is created through diffraction. The size of the spheres determine
the wavelengths and therefore the colors seen. The brilliance of the colors are
determined by the regularity of the grid.
The strength of the colors seen in opal also depend on the background body color
and the transparency of the stone. The body color determines the variety of opal
and has a large impact on the value.
Black opal, opal with a black to dark gray body color, has the most brilliant
colors and is the most valuable. Crystal opal, the next most costly type of
opal, is transparent with flashes and is highly valued due to the brilliance of
its colors and the fact that many layers of color within the stone can also be
seen. White and milky opals tend to have more diffused colors due to the light
background color. This is the most affordable type of opal.
Another more unusual type of opal is boulder opal, which has opal with an
ironstone host rock matrix which creates a natural dark background to view its
fire. These sometimes occur in "splits" a matched pair of opals
created when a piece of boulder opal is split along the opal vein. These are
particularly favored for earrings, since they are mirror images of each other.
Choosing an Opal
Within each opal variety, the brillance of the play of color is the most
important value factor. After this consideration, the colors seen and the
pattern of the colors will also influence value. Generally, opal with red fire
is the most valued because opal that shows red will also show other colors when
rolled back and forth: it contains the whole spectrum. The pattern of the play
of color also influences value. Generally large flashes and broad patterns are
more rare and valuable than small pinfire patterns.
Black opal is found only in Australia in Lightning Ridge, the most famous opal
deposit in the world since it was discovered in 1903, and in Mintabie, which
also produces large quantities of light opal.
Another large opal producing area in Australia is Coober Pedy, which produces
light opal. The name Coober Pedy is an Aboriginal name meaning "white man
in a hole." If you visit Coober Pedy, you will understand how it got its
name: many houses - and even a church! - are burrows dug into the ground called
dugouts. This type of dwelling is quite practical and cool as temperatures soar
in the daytime.
Andamooka is known for producing crystal opal and light opal. Boulder opal is
produced in several areas in western Queensland.
In addition to Australia, a small quantity of precious opal is produced in
Brazil. Mexico and the state of Oregon in the United States produce a volcanic
opal called fire opal. Fire opal is transparent opal ranging in color from
colorless to yellow, orange, and red. Sometimes it also shows play of color in
addition to its bright orange body color. Low quality opal was recently
discovered in Ethiopia.
Opal is cut in Australia, Hong Kong, Mexico, Germany, and other places.
Calibrated sizes are widely available in light opal, which is very popular with
jewelry manufacturers around the world due to the beauty even of inexpensive
pieces. Black opal is cut in free sizes due to its rarity and high value.
Boulder opal is often available in the natural shape of the rough. Fire opal can
be found in both faceted and cabochon cuts, including many interesting fancy
shapes.
A green translucent opal that resembles chrysoprase or jade, which is called
prase opal, is found in Tanzania. A beautiful blue-green opal is found in Peru
in the Andes Mountains. These types of opal do not display play of color.
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