Opal - October
Birthstone
Opal is a paradoxical
gemstone, and one of the most fascinating.It is a form of quartz, but is
not a form of quartz.Opal itself has numerous varieties. It is the most
colourful gemstone, but some forms are colourless. It can be very bright
and beautiful, and it can be dull and dead. It is best known for its
flashes of colour, but some varieties have no flashes of colour, and are
still opals. It can be black, and it can be white. Its best known
attribute, the brilliant flashes of many colours, are not called
opalescence, but irridescence.
Opal as
Muse
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 sparkled with the color
of bright ruddy wine, and was overcome by this
radiance."
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."
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.
Sources for this
Gemstone
Ancient
opal came from the mines near Cervenica, Hungary, in what is now Eastern
Slovakia, Australia and Translucent green opal in
Tanzania.
Technical
Details
| Chemical Composition
and Name |
SiO2nH2O - Hydrous
Silicon Dioxide |
| Hardness |
5.5 to
6.5 |
| Refractive
Index |
1.44 -
1.47 |
| Specific
Gravity |
1.95 -
2.20 |
| Crystalline
System |
Gel |
| Other Optical
Properties |
Isotropic |
