The blue sapphire is made of the mineral corundum (aluminum oxide). Its attractive blue color is due to traces of the elements iron and titanium. Commonly, the sapphires are heat-treated, called ‘thermal enhancement,’ in order to deepen the intensity of their color. Untreated sapphires are very rare and much more expensive than those which have been treated.
Blue sapphires are a natural phenomenon found all over the world, for example in Australia, Cambodia, Laos, Vietnam, Thailand, Sri Lanka, Madagascar, Cameroon, Tanzania and Nigeria.
Several shapes of heat-treated sapphires are manufactured by richblu : rounds, ovals, pears, marquises, octagons, etc. They are available in a variety of calibrated sizes. To find out the calibrated sizes we customarily stock, click here.
richblu can also offer precision-cut blue sapphires, that is,gems that are finely cut and crafted to elevate them to their maximum brilliancy. Our skilled craftsmen use specialist automated machines to produce the finest precision-cut gems. If you are interested in precision-cut sapphires, contact us for more information
|Formula||Aluminium oxide, Al2O3|
|Color||Typically blue, but varies|
|Crystal habit||As crystals, massive and granular|
|Space Group: R3c|
|Mohs scale hardness||9|
|Optical properties||Abbe number 72.2|
|Melting point||2,030–2,050 °C|
|Other characteristics||Coefficient of thermal expansion (5.0–6.6)×10−6/K|
|relative permittivity at 20 °C|
|ε = 8.9–11.1 (anisotropic) |