Sapphire, a variety of the mineral corundum, is found in almost every color, except for red. That's because red corundum is known as ruby, while all the other colors of corundum are known as sapphire.
Corundum itself is not a very rare mineral. Since it is extremely hard (9 on the Mohs scale) it is used industrially to produce abrasives, from sandpaper to large devices for machining metal, plastic and wood. Gemstone quality corundum is very rare; most corundum is opaque, translucent or heavily included.
Sapphire is found in only a few locations in the world. The most famous sapphire sources are in Asia, especially Burma, Thailand, Sri Lanka and Kashmir. Sapphire has also been mined in Cambodia, Vietnam and India. In Africa, Madagascar and Tanzania have recently become important sources for sapphire. Australia has significant sapphire deposits, though the Australian sapphire is famously dark. In the USA there are small sapphire deposits in Montana and North Carolina.
The finest quality blue sapphire that commands the highest auction prices comes from Kashmir and Mogok, Burma. These sapphires are rarely seen on the market. The bulk of today's supply comes from Sri Lanka and Madagascar, with some additional supply from Thailand, Tanzania and Australia.
Both Sri Lanka and Madagascar produce sapphires in a wide range of colors. Sri Lanka has been a source of fine sapphire for centuries, but the Madagascan deposits are very recent finds. Indeed, the enormous sapphire deposits discovered in 1998 in the tiny village of Ilakaka came as a complete surprise and led to a kind of gemstone fever not unlike the gold rush of California in the mid-19th century. Since 2007, Madagascar has led the world in sapphire production.
Green Madagascan Sapphire
The finest Kashmiri and Burmese rubies display superb color and clarity without any thermal treatment. Some Sri Lankan sapphires are also unheated. However, the vast majority of the sapphires on today's market, whether from Sri Lanka, Madagascar, Tanzania or Thailand, have been heat treated to improve the color and clarity.
Sapphire rough from many locations is processed and cut in Thailand, especially in our home of Chanthaburi on the Eastern Seaboard of Thailand. Chanthaburi Province was one of the two main sources for Thai sapphire (the other is Kanchanaburi). Nowadays, sapphire mining in Chanthaburi is mainly finished, with the exception of the black/gold star sapphires, which are found nowhere else in the world. Now Chanthaburi has become the main global trading center for sapphire and ruby.
- First Published: December-13-2007
- Last Updated: April-23-2019
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