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March Birthstone - Aquamarine
Physical and Chemical Properties
Chemical composition
Aquamarine is the mineral Beryl, a Beryllium Aluminum Silicate with the general
chemical formula Be3Al2(Si16O18).
It ranges in hardness from 7 2 to 8 on Moas
scale; it has an imperfect cleavage and a vitreous luster. Optically, beryl is
uniaxial negative; some specimens may be strongly diachronic; its refractive
index ranges from about 1.57-1.58 or to 1.58-1.59. Aquamarine crystals are often
elongated along the c-axis whereas emerald crystals are often blunted along the
c-axis. This creates the effect of the former appearing wand-like or pencil-like
whereas the latter may appear barrel-like. Other mineral beryls include emerald,
morganite, and heliodor.
Colors
Aquamarine ranges from pale blues to light blues to yellowish blues and also may
appear to be green or greenish-blue. They may be heat treated to intensify their
color.
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