To anyone who has ever admired the brilliant color and shine of a polished sapphire gem, this may be hard to believe: a sapphire is formed from a clear and colorless mineral, dialuminum trioxide.

Only when impurities appear in the mineral do they have color. Iron makes for a yellow gem, iron and titanium cause them to have a blue shine, and chromium makes for a red stone.

Red sapphires, some of the most treasured for gemstones, are also known as rubies. Only diamonds are harder and sapphires have been used for several practical purposes as an abrasive, cutting and polishing material. They have been employed as phonograph needles, nail files, bearings for machinery, and in their refined form as beautiful jewels.

The recent development of heat treating technology has dramatically increased the demand for sapphires as jewelry.

Most sapphires contain titanium oxide, an impurity that creates a hazy appearance in the gem. When these stones are heated to very high temperatures, the titanium crystals dissolve into the surrounding minerals and reveal the gemstone's natural brilliance.

Polishing and faceting the sapphires further brings out their vibrant natural colors.

The brilliant colors revealed by the heat treatment process can range from cornflower blue to reddish orange to sage green.

There is more variety in the sizes and colors found among Montana sapphires from Gem Mountain than anywhere else in the world.