Sapphire
Corundum group
Color: blue, colorless, yellow, pink, green, orange, purple, black
Moh's hardness: 9
The name sapphire is Greek and means "blue". Around 1800 it was recognized that sapphire and ruby were actually members of the same gemstone family: corundum. At first only the blue variety was referred to as sapphire but today corundums of all colors, except red, share that name.
Gemstones in the corundum group consist of pure aluminum oxide. The presence of small amounts of elements such as iron and chrome are responsible for turning a crystal that was basically white into blue, red, yellow, pink or green, hence the array of colors represented in sapphires.
Sapphires are characterized by their excellent hardness (9 on the Moh's scale), exceeded only by that of the diamond: the hardest mineral on Earth. Sapphires are therefore easy to look after and do not require more than the usual care.
Sapphires are found in India, Burma (Myanmar), Sri Lanka, Thailand, Vietnam, China, Cambodia, Australia, Brazil, Kenya, Malawi, Tanzania and Zimbabwe. Connoisseurs regard the Kashmir color, a pure, intense blue with a very subtle violet undertone and silky shine as the most beautiful and valuable blue. The Burmese color, which ranges from a rich, royal blue to a deep cornflower blue, is also regarded as particularly valuable. Ceylon sapphires are characterized by the luminosity of their light to mid-blue colors.
The value of a sapphire depends on its size, color, transparency and country of origin. The most valuable are genuine Kashmir sapphires. Burmese sapphires are valued almost as highly, followed by sapphires from Ceylon. Most blue sapphires on the market come either from Australia or Thailand.
For centuries, the sapphire has symbolized loyalty and love which explains the popularity in many countries of using this precious gem in engagement rings.