Sapphire

History
According to legend, when Moses was handed the 10 commandments he received them on tablets of sapphire, a rich blue stone, though according to a description of the tablets provided by Pliny, they were probably made of lapis lazuli. The word for sapphire comes from the Latin "sapphirus" meaning "blue".

Features
Like ruby, sapphire is a corundum, and only diamond is harder than it. Crystals are six sided, and are frequently shaped like long double ended six sided pyramids. Sapphires come in a wide range of colors, from colorless to pale yellow, to pink, with blue being the most famous and the most common. As with ruby, sapphires can range in clarity from crystal clear to heavily included. Sapphires also come in star stones.

Treatments
A common treatment for sapphires is heating. Many sapphires start life either too pale or too dark. Heating the sapphires can improve their color and turn them into a more desirable shade of blue. Fancy colors, like the pinkish-orange padparadscha sapphire, highly prized in India, is often the result of diffusion treatment of a paler pink sapphire.

Principal Deposits
Australia produces many of the world's top quality sapphires, as does Sri Lanka. Kashmir has long been a source of the world's finest blue sapphires, and India, Tanzania and the US also have some production.

Rarity
As with any quality gemstone, an exceptionally clear blue sapphire of magnificent color is hard to find. A genuine padparadscha sapphire of good color and clarity, highly prized by people from India and Japan, is even more rare than a fine blue. Star sapphires which have good color and display a well formed star is equally rare.