Sapphires are the crystalized form of the mineral corundum. Every shade of crystalized corundum except those that are distinctly red fall into the sapphire family. A red carborundum crystal is classified as a ruby. Sapphires are found in Thailand, Kashmir, Australia, Madagascar, India, Burma, Sri Lanka and right here in the United States -- mainly in Montana. The three regions most famous for blue sapphires are Kashmir, Burma and Sri Lanka. At 9 on the Mohs Scale of Mineral Hardness, sapphires and rubies are among the hardest materials known to man -- second only to diamond.
Kashmir sets the standard for blue sapphires. The more intensely saturated the hue, the more rare and valuable the gem.
It was unusual for a royal to select a ring that was not custom-made, but part of a jeweler's collection; even if that jeweler was Garrard's -- the world's oldest jewelry house. Even so, Dianna's 12 carat Ceylon Sapphire ring became iconic and inspired hundreds, if not thousands of knockoffs. In 2010, when Prince William proposed to Kate Middleton, he presented her with his mother's engagement ring.
Extremely rare and prized by gem collectors, padparadscha sapphires are named for the ancient Sanscrit word for "lotus blossom". These beautiful sapphires are said to to have a color that is"the marriage of a lotus flower and the sunset". The finest padparadscha sapphires are mined in Sri Lanka.