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| Tourmalines of New York
Tourmalines are a group of complex silicates of aluminum and boron belonging to the hexagonal crystal system. Compositions vary
widely as sodium, calcium, iron, magnesium, lithium, manganese and fluorine enter the structure. Tourmalines occur in a variety of
colors caused primarily by differences in chemical composition. Usually, iron-rich varieties are black, magnesium-rich varieties are brown
to yellow, and chromium-bearing varieties are green.
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Tourmalines occur in two main types of geological environments; igneous rocks, particularly in granites and pegmatites and metamorphic rocks
such as schists and marbles. Tourmalines have scientific significance providing information on the thermal and fluid history of the rocks in
which they form and are an important component in the boron cycle on Earth. Tourmalines are also cut as gemstones and used in jewelry.
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The tourmaline group is currently the object of mineralogical research here at the New York State Museum. Schorl, dravite and uvite are
the tourmaline species that have been identified, up to this point, as occurring in New York.
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