Sapphire:
All gem quality corundum that is not red is called sapphire, yet this name is popularly associated with the color blue. Variation in color, due to iron and titanium impurities, spans many shades, but the most valuable is a clear deep blue. Some stones, called “color change sapphire”, exhibit different shades of blue in artificial and natural light.

Occurrence:
Good quality sapphire is found in Burma , Sri Lanka , and India . The best Indian sapphire is cornflower blue and found in Kashmir , either in pegmatites or as water worn pebbles in alluvial deposits. Sapphire from Thailand , Australia and Nigeria is dark blue, and may appear nearly black. Montana (USA) produces sapphire of attractive metallic blue. Other localities include Cambodia , Brazil , Kenya , Malawi and Colombia .

Remark:
Synthetic sapphire production began in the late 19th century. Commercial quantities became available in the early 20th century.

Padparadscha:
Padparadscha is very rare, pinkish orange sapphire. It is the only variety of corundum other then ruby that is given it’s own name, rather then being referred to as sapphire of a particular color. The name derives from a Sinhalese word, meaning lotus blossom.

Occurrence:
Sri Lanka

Remark:
Like all varieties corundum, Padparadscha is an excellent jewelry stone as it is second only to diamond.

Yellow Sapphire:
Up until the3 end of the 19th century, yellow sapphire was known as "oriental topaz" (only blue corundum was called sapphire). Nevertheless yellow and greenish yellow sapphire make unusual and attractive gemstones in there own right.

Occurrence:
Queensland and New South Wales (Australia), a greenish yellow sapphire is found that may be faceted. Similar stones occur in Thailand, and purely yellow stones in Sri Lanka, Montana and East Africa.

Colorless sapphire:
The different colors found within members of the corundum group are due to small amounts of metal oxide impurities. Corundum without impurities (and therefore without color) is rare, but when found is classified as colorless sapphire. Stones made up of different colors, including colorless areas are more common.
Stones like these are generally oriented by the cutter so that the color is at the base. Then when viewed from above, color fills the stone.

Occurrence:
Truly colorless sapphire is found in Sri Lanka. Cloudy or milky colored sapphire is also found in Sri Lanka, and referred to locally as geuda.
Heat treatment of geuda produces blue sapphire, much of which is faceted and used in jewelry. Some Sri Lankan corundum shows red, blue and colorless areas, which may be faceted or polished to give an interesting stone.

Remark:
Synthetic colorless corundum has been produced by the Vemeuil method since the 1920's and has been called diamondite.

Green Sapphire:
From medieval times until the end of the 19th century green sapphire was referred to as "oriental peridot". Many sapphires that appear green actually consist of very fine alternating bands of blue and yellow sapphire, which may be visible under a microscope.

Occurrence:
Green sapphire are found in Thailand, Sri Lanka' and Australia.

Pink Sapphire:
Pure pink sapphire is colored by very small quantities of chromium, and with increasing amounts of chromium it forms a continuous color range with ruby. Tiny amounts of iron may produce pink orange stones called Padparadscha or iron and titanium impurities together may make purplish stone.
Pink sapphire are often cut with a deep profile.

Occurrence:
Pink sapphire from very pale and delicate pink to a near red occur in Sri Lanka, Burma and East Africa.

Remark:
Like rubies pink sapphire are believed to ward of illness and misfortune. For the wearer to gain the benefit of the stone, however, it is thought necessary for it to be worn directly on the skin. Therefore stones are cut so that when set in a piece of jewelry, the back makes contact with the skin.