Mineral Resources Potential - Geothermal Resources

6.1 Corundum (ruby and sapphire)
Sapphire is the single-crystal form of aluminium oxide (A1203), a
mineral known as corundum. It can be found naturally as
gemstones or manufactured in large crystal bodes for a variety of
applications. The corundum group consists of pure aluminium
oxide. Trace amounts of other elements such as iron and chromium
give sapphires their blue, red, yellow, pink, purple, orange or
greenish color. Sapphire includes any gemstone quality varieties of
the minerd corundum including the red variety, which is also
known as ruby. Ruby is a red gemstone, a variety of the mined
conmdum (aluminium oxide). The color is caused mainly by
chromium. Its name comes hm ruber, Latin for red. Natural
rubies are exceptionail y rare, but synthetic rubies (sometimes
called created ruby) can be manufactured fairly cheaply. Other
varieties of gemquality corundum are called sapphires. It is
considered one of the four precious gems together with sapphire,
the emerald and the diamond.
Rubies are mined in Africa, Asia, Australia, and Greenland.
They are most often found in Myanmar (Burma), Sri Lads
Kenya. Madagascar, and Thailalld, but they have also been found
in the U.S. states of Montana, North Carolina and South Carolina,
The Mogok Valley in Myanmar has produced some of the finest
rubies, but in recent years very few good rubies have been found
there. In central Myanmar the area of Mong Hsu also produces
rubies. The latest ruby deposit to Lx found in Myailmar is situated
in Narn Ya. In 2002 rubies were found in the Waseges River area
of Kenya. Rubies are being mined at Audilamena in northeastern
Madagascar. Sometimes spinels are found dong with rubies in the
same rocks and are mistaken for rubies. However, fine red spinels
may approach the average ruby in value. Rubies have a hardness of
9.0 on the Mohs scale of minerd hardness. Among the natural
gems oqly diamond is harder.