Kashmir, in India, used to be a well-known source of the cornflower-blue stones. Found in alluvial deposits of weathered basalt, Australian sapphires typically are blue stones with a dark and inky appearance. The biggest source of sapphires world-wide is Australia, especially New South Wales and Queensland. For example, yellow sapphires get their color from ferric iron, and colorless gems have no contaminants. Different kinds of impurities within the crystal cause the various gemstone colors. Sapphires also occur in other natural colors and tints – colorless, gray, yellow, pale pink, orange, green, violet and brown – called fancy sapphires. The most valued shade of blue is the medium-deep cornflower blue. They range from very pale blue to deep indigo, with the exact shade depending on how much titanium and iron lies within the crystal structure. Typically, sapphires appear as blue stones. That makes sapphire second in hardness only to diamond. All corundum, including sapphire, has a hardness of 9 on the Mohs scale. And all other gem-quality forms of corundum are called sapphires. Both are forms of the mineral corundum, a crystalline form of aluminum oxide. September’s birthstone, the sapphire, is a relative of July’s birthstone, the ruby.
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