CHEMISTRY: Al2O3
CRYSTALLOGRAPHY: Hexagonal
REFRACTIVE INDEX: 1.757 - 1.779
HARDNESS: 9
SPECIFIC GRAVITY: 3.99 - 4.0
CLEAVAGE: None
HEAT SENSITIVE: No
WEARABILITY: Excellent
SPECIAL CARE INSTRUCTIONS: None
ENHANCEMENTS: Heat treated. Common. Diffusion
treatment, (places a thin blue coating on colorless sapphire.) Occasional.
Irridation, (turns colorless gems yellow, orange or light blue.) Rare.
Wearability: Excellent
Sapphire: Birthstone
for September
Sapphire is often considered to be synonymous with the color blue. However,
sapphie comes
in every color but red. Red is called ruby. The other colors of sapphire
can be just as beautiful and rare. Or even more rare than blue. Some
are even considered to be collectors items. However, they are usually
priced less. Yellow, orange, lavender, and other pastel shades are especially
affordable.
Since our ancestors did not realize that ruby and sapphire are actually
the same mineral, they left us with a dilemma: where should pink shades
be classified? Long ago, people decided to call all gemstones of the
mineral corundum as sapphire, except the red color, which was called
ruby. But pink is really just light red.
The International Colored Gemstone Association has passed a resolution
that the light shades of the red hue should be included in the category
ruby since it was too difficult to legislate where red ended and pink
began. In practice, pink shades are now known either as pink ruby or
pink sapphire. Either way, these gems are among the most beautiful of
the corundum family.
The ancient Persians believed that the earth rested on a giant sapphire
whose reflection gave the sky its color. Damigeron, a historian of old,
wrote that sapphire was worn by kings to protect them from harm. It
was also believed that sapphire would protect the wearer from envy and
attract divine favor. The gem was regarded as a symbol of truth, sincerity
and constancy.
Legend has it that if a poisonous snake were put into a vessel along
with a sapphire, the rays from the gem would kill it. Our ancestors
interpreted this to mean that sapphire was an antidote against poison.
At one time. Any blue gem material was called sapphire. References to
a blue-flecked stone, led mineral experts to realize that some of what
had been called "sappheiros" was actually lapis lazuli. "Sappheriros"
is Greek for "blue." From the Mountains of Kashmir The finest sapphire
color is rich, velvety cornflower blue. This is called "kashmir" out
of the deference to the traditional source of the finest quality.
Today, however, the Kashmir area of India is not generally mined because
of its physical inaccessibility. Most current production comes from
Sri Lanka, Burma, Thailand, Montana, Australia and Africa.
The most valuable other fancy sapphire is a orange-pink or pinkish-orange
called "padparadscha" after the lotus blossom. Padparadscha sapphires
are very rare and the exact definition has always been a matter of debate:
different dealers and different laboratories around the world disagree
on the exact color described by this term. Some dealers even argue that
the term should not be limited to the pastel shades of Sri Lankan sapphires
but should also include the more firey shades of reddish-orange from
the Umba Valley in Tanzania.
Star Sapphires have fine, needle-like inclusions called asterism. When
these inclusions are numerous enough to make the stone translucent or
opaque and are oriented properly, they allow light to be reflected in
such a way that a moving star forms across the top of the stone. When
a cutter recognizes this potential in a piece of rough sapphire, he
will cut it in a dome shape. Stars are not visible in faceted stones.
The Sinhalese believed the star sapphire would protect them against
witchcraft. The three intersecting rays were thought to represent faith,
hope and destiny. Museums the world over exhibit star sapphires that
are noteworthy for size or quality. The 543-carat "Star of India" resides
in the Morgan-Tiffany Collection in the American Museum of Natural History
in New York City.
Major Deposits and Characteristic Colors:
AFRICA:
Africa has numerous deposits of gem quality corundum and has recently
been a source of new sapphire and ruby discoveries.
Tanzania:
UMBA River - Some blue, lavenders and purples to plums, yellows, golds
to orange browns, pinks, and padparadschas.
SONGEA:
Deep red rubies, blues, blue greens, greens, yellows, pinks, alexandrite-type
(blue in sunlight and fluorescent light, lavender to purple in incandescent).
TUNDURU:
Full spectrum of colors.
Madagascar:
Blue, very much like Sri Lankan blue. The rubies are clear red and often
unheated. Range of pink from pale to intense.
Kenya:
LODWAR - Clear deep blue to very dark blue-green and an abundance of
opaque blue stars.
GARBATULA:
deep, blackish blue-green to intense pleasant green.
ASIA:
Sri Lanka
The island nation south of India was known as Ceylon for many generations.
Consequently "Ceylon-blue" is a color name outliving the change in national
name. Sapphires of note in large sizes - over 5 carats - of outstanding
color are predominantly of Sri Lankan origin. White, blue, purple, pink,
yellow, gold, and padparadaschas.
Mysore (India)
Star rubies.
Myanmar (Burma)
Ruby and sapphire mines of Burma are legendary and have produced some
of the world's finest rubies and blue sapphires.
MOGOK STONE TRACT:
Star rubies, star sapphires, rubies. Sapphire - violet, yellow, color-change,
and blue.
MONGSHU:
Ruby.
TADJIKASTAN:
Ruby.
Thailand (Siam)
Thailand is a traditional supplier of sapphire and ruby. The majority
of sapphire production from the Kanchanaburi field has been mined in
the last ten years. This deposit is approaching depletion.
CHANTABURI:
blue, rubies, dark blue, green, yellow, and black star - 6 and 12 ray.
KANCHANABURI:blue and green, yellow and
rubies.
Vietnam: Rubies and sapphires have been
found in Vietnam since the late 1980's. They are very rarely seen in
the jewelry market.
LUC YEN AND QUY CHAU:
red and red-pink rubies, hot pink and purple sapphire.
Cambodia:
PAILIN - blue sapphire and color change ruby.
AUSTRALIA:
Australia also has several deposits and contributes greatly to the sapphire
jewelry market in mostly Inky blues to less known brilliant true blues,
green, blue-green, yellow-green, yellows, oranges, and some pinks.
NORTH AMERICA:
Montana
Montana has four main deposits:
DRY COTTONWOOD CREEK:
yellow, gold and green, some pink, blue, and very, very rarely a ruby.
MISSOURI RIVER:
green, blue, yellow, orange, pink, and very rarely ruby.
ROCK CREEK:
full spectrum of colors including many bicolors, and also very rarely
ruby.
YOGO GULCH:
blue and purple.
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