SAPPHIRE is a are part of the corundum family, one of the strongest minerals on earth. The stone is mined in many parts of the world, including Australia, Cambodia, China, Kashmir, Kenya, Madagascar, Myanmar, Nigeria, Sri Lanka, Tanzania, Thailand, the United States and Vietnam. Sapphires from Kashmir and Myanmar are rarest and most prized because of their vivid blue, velvety look.
Although sapphire is virtually synonymous with blue, the stone also comes in a variety of fancy colors that includes colorless/white, pink, yellow, peach, orange, brown, violet, purple, green and many shades in between (except red, because a red sapphire would be called a ruby). Some sapphires that are cut into a cabochon (dome) shape even display a six-rayed white star. These are called star sapphires, and the ancients regarded them as powerful talismans that protected travelers.
Sapphire is readily available in sizes of up to 2 carats, but gems of 5-10 carats are not unusual. The stone is most often cut in a cushion shape - a rounded rectangle - or an oval. But smaller stones are available in round brilliant cuts and a variety of fancy shapes, such as triangle, square, emerald, marquise, pear, baguette, cabochon and others.
With a hardness of 9 on the Mohs scale, sapphire is harder than any other gemstone except a diamond. This quality makes it extremely durable for everyday jewelry pieces subject to repeated impact, such as rings and bracelets. In general, sapphire can be cleaned with soapy water or commercial solvent and a brush.
It is estimated that about 90% of sapphires on the market today have been heated to maximize their color and clarity. This process is permanent and completely stable. Perfect natural, untreated gems are exceptionally rare and very expensive. Some colorless or pale stones are treated with chemicals (diffusion treated), which improves the surface color only. This could create a problem if the stone is ever chipped or nicked and needs to be recut or repolished. In addition, some fancy colored sapphire is irradiated to give it a more intense shade. These effects are temporary and can fade in light or heat.
