According to Arabic legend, opal was believed to contain lightning.
Writers have compared opal’s color to volcanoes,
galaxies and fireworks. Admirers gave extraordinary
opals poetic names like Pandora, Light of the World and
Empress. In ancient Rome, this gem symbolized love
and hope. The Romans gave it a name—opalus—that
was synonymous with “precious stone.” Many cultures
have credited opal with supernatural origins and
powers. The ancient Greeks believed opals gave their
owners the gift of prophecy and guarded them from
disease. Europeans have long considered the gem a
symbol of hope, purity and truth.
Opals display a phenomenon known as play-of-color.
When a stone has play-of-color, it is referred to as
precious opal. The main categories of precious
opal are white, black, boulder, and crystal or water.
Fire opal, also known as Mexican opal, sometimes
doesn’t show play-of-color.
With an opal, clarity is its degree of transparency and
freedom from inclusions. An opal’s clarity can range
all the way from completely transparent to opaque.
A cloudy or milky background color can sometimes
signal a lack of stability. Opals can have fractures and
surface blemishes. Matrix, or host rock, along with signs
of crazing, a fine network of cracks, have an impact on
opal’s durability and value.
Fine opal comes from all over the world. The most
significant sources are Australia, Mexico and Ethiopia.
Opals can be treated by impregnation with oil, wax or
plastic. Opal doublets or triplets are thin slices of opal
glued to a base material and covered with a thin dome
of clear quartz. These gems are more resistant to
scratching but are considered less valuable. Some
opal can be dyed.
All information are courtesy of Gemological Institute of America (GIA). OR DIAMOND are not affiliated with, connected to, or associated with GIA other than selling diamonds and gemstones graded by GIA and have GIA trained staff gemologist and accredited jewelry professional on site.