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Tourmaline is a complex crystalline silicate
containing aluminum, boron and other elements. Its name is derived from the
Sinhalese (Sri Lanka) word tura mali, meaning "stone of mixed
colors." Indeed, tourmaline appears in blue, yellow, pink, red, black,
green and clear, sometimes all on the same stone and sometimes one color
per stone.
Tourmalated quartz contains black
tourmaline inclusions and
green tourmalated quartz contains
green inclusions. Each color of tourmaline is given its own name in the gem
world, making tourmaline more a group of minerals than a single type. These
include rubellite (pink to red), indicolite (blue), schorl (black), dravite
(brown) and achroite (colorless).
Tourmaline boasts a
number of rather amazing physical characteristics. For one, it is
piezoelectric; this means heating, rubbing or pressurizing the crystal gives
it an electric charge, attracting small objects such as hair or small pieces
of paper. Because of this property, tourmaline has been employed in
depth-sounding devices and other tools that detect and measure variations in
pressure. It also is pleochroic, looking darker from some angles than from
others. As with all gems, protect tourmaline from scratches and sharp blows,
and avoid drastic temperature changes. Do not clean tourmaline in a home
ultrasonic cleaner.
Tourmaline has been
used as a gem for more than 2,000 years. An ancient Egyptian legend attempts
to explain the beautiful array of colors in this gemstone: On the long
journey from the middle of the earth up toward the sun, the tourmaline
traveled along a rainbow. On the way, it collected all the colors of the
rainbow, which is why it came to be known as "the rainbow gemstone." In
medieval times, tourmaline was thought to heal physical and mental
disorders, and prevent death.
Tourmaline is mined
around the world but has important occurrences in Brazil, Sri Lanka and
southern Africa. Others include Pakistan, Afghanistan, the U.S.A. (Maine and
Utah), Mexico and Myanmar (formerly Burma).
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