When hearing the word “sapphire,” most people visualize a blue gemstone, but sapphires can be any color of the spectrum except red, which is reserved for ruby. Sapphire and ruby are color varieties of the same species, corundum, and only differ in the amount of trace
elements coloring the material. In the case of blue sapphire, the coloring elements are iron and titanium; yellow and green sapphires are both colored by iron; chromium produces a pink sapphire; and iron, with vanadium and a trace of chromic oxide, forms the rarest sapphire of all – the padparascha sapphire. This orangey-pink stone is named after a common lotus flower in Sri Lanka, where it originates. Other localities for sapphire include Burma (Myanmar), Sri Lanka, (Ceylon), Thailand, Cambodia, Vietnam, Australia, Montana, and Madagascar in Africa.
All sapphires are quite hard, second only to diamond, and are tough enough to wear in rings and other forms of jewelry without worry. Because of this hardness, sapphires take a wonderfully bright polish and scratch only with difficulty. The most highly prized type of blue sapphire is called “Kashmir,” a medium to medium-dark slightly violetish-blue color with a distinctive “hazy” quality. The mine where these exceptional stones originate is now mined out and no longer supply any material. Often found in estate jewels, a Kashmir sapphire is indeed of mystical beauty.
Beautiful sapphires also come from Burma (Myanmar), and approach the quality of the Kashmir stones in color without the hazy texture, yielding a brighter version which are preferred by some.
Star sapphires form when microscopic needle-like inclusions of rutile crystals align in a three-fold symmetry and
create a star on the surface of a cabochon cut stone. Sapphire crystals can occur in quite large sizes; the heads of presidents Washington, Lincoln, and Eisenhower have been carved out of some of these larger crystals, each weighing approximately 2,000 carats. Other famous sapphires include the Star of India, a 536 carat star sapphire in the American Museum of Natural History, and the 330 carat Star of Asia, owned by the Smithsonian Institute in Washington, D.C.
Variety: Sapphire, star sapphire
Chemical Composition: Al2O3
Color: varying tones and saturations of blue, violet, pink, orange, yellow, green and colorless.
Crystal System: Hexagonal
Refractive Index: 1.762 - 1.770 (+.009, -.005)
Specific Gravity: 4.00 (+.10, -.05)
Images by Jack Abraham.