Sapphire Gemstone

The sapphire is one of the most valued gemstones. It is sought after on account of its excellent colour, hardness and lustre. In the trade, the term ‘sapphire’ without colour prefix depicts the blue variety of the mineral corundum. However, the term ‘sapphire’ includes all other gemstone varieties and colours of corundum except for ruby, the red variety of corundum which has had it own name since antiquity.

The Sapphire is one of the most popular gemstones and is widely used in jewellery. Nicely coloured,  deep blue sapphire can fetch several thousand dollars per carat. The blue variety is most common in jewellery but yellow, pink and orange ‘fancies’ have recently become popular. Green and light blue sapphire exist but are less common in jewellery. Opaque, black sapphire is uncommon.

Sapphire is used in all types of jewellery such as bracelets, necklaces, rings and earrings. It is used as the main gemstone in pendants and rings and also as secondary gemstone to complement other gemstones such as diamonds. Star sapphire is polished as cabochons and are very valuable if they are clear.

Properties

Mineral group:  Corundum
Chemistry: Aluminiumoxid Al2O3
Color: Every color except red (which is ruby) or pinkish-orange (padparadscha)
Crystal system: Trigonal
Mohs Scale hardness: 9
Refractive index: 1,766-1,774
Birefringence: 0,008
Specific gravity: 3,97-4,05

Information