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Chemical Formula: (Na,Ca)(Mg,Li,Al,Fe2+)3Al6B3Si6(OH)4
Mineral Name: Tourmaline
Color: Varying shades of green, red, blue,
yellow, brown, black etc
Hardness: 7 - 7.5
Specific Gravity: 3.03- 3.25
Tourmaline is a complex crystalline silicate
containing aluminum, boron and other elements, used in
electronic instrumentation and, especially in its
green, clear, and blue varieties, as a gemstone. Its
name has been derived from the Singhalese expression "tura
mali" meaning stone of mixed colours. The name refers
to the unique spectrum of colors displayed by this
gemstone. Tourmalines are red and green, range from
blue to yellow. There are Tourmalines, which change
the color from daylight to artificial light and others
display chattoyance.
Tourmaline is predominantly used as a jewelry stone,
although it is also used in pipe cleaners (as in, the
kind of pipes you smoke) due to it's piezoelectric
properties which cause the soot to grasp on. It can be
cut and polished a number of ways. Some tourmaline can
exhibit a much-desired "cats-eye" effect when cut into
a cabochon (sphere). Heat treatment of tourmaline can
enhance the color. Some pink, green, and multicolored
tourmalines are also carved into ornamental figures
and carvings. Tourmaline is found in Africa, Brazil,
Madagascar, Mexico, Myanmar, Namibia, Sri Lanka and
USA.
