CORUNDUM VARIETIES
Primarily mined from Alluvial deposits, the majority of Sri Lankan corundum are variants of Geuda and Ottu and is commercially known under three variants; namely sapphires, rubies and Padparadscha sapphire. In fact, the name sapphire can apply to any corundum that’s not red and doesn’t qualify as ruby, another much sought after corundum variety.

Besides blue sapphire and ruby, the corundum family also includes gemstones known as fancy sapphires which are found in violet, green, yellow, orange, pink, purple, and intermediate hues. Fancy sapphires can also be particoloured sapphires that show combinations of different colours. Some stones exhibit the phenomenon known as colour change, often altering between blue under the daylight or fluorescent lighting to purple under incandescent light.

In addition, corundum can result in sapphires that are also white, grey, black, or brown. Corundum also shows a phenomenon called asterism or the star effect, which usually appears as a sixray star pattern across a cabochoncut stone’s curved surface. Most visible in any colour of sapphire, it arises from white light reflecting from tiny, oriented needlelike inclusions. Sri Lanka is also a source of large star sapphires of premium quality and some of the largest star sapphires in the world including the Star of Adam