4.57ct Blue-Green Colour Octagon Cut Sapphire Certified Unheated 9.9x7.8mm

This unheated sapphire is accompanied by a certificate from GIA. Sapphire is a variety of the mineral corundum, an aluminium oxide. It is typically blue but fancy coloured sapphires also occur in orange, yellow, green, brown, purple, pink, black and colourless. Red and reddish-pink coloured corundum is referred to as ruby. The variety in colours is due to trace amounts of elements such as iron, titanium, chromium, copper and magnesium. Mohs Scale of Hardness: 9 (out of 10). Sources: Mines that have yielded the finest sapphires in colour and clarity are located in Kashmir, Myanmar and Sri Lanka. Nowadays the main sources of sapphires are: Thailand, Cambodia, Australia, Madagascar and Montana in the U.S.A. ;Stone Size (mm): 9.89x7.85x5.63mm;Carat Weight (ct): 4.57