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Phenakite
Phenakite is a rare, colorless mineral stone that is sometimes also
found in tinted yellow, brown and pink shades. The name Phenakite is from
the Greek word 'Phenakos' meaning "Deceiver", referring to its deceptively
similar look to Quartz.
Phenakite is a beryllium mineral found as vitreous crystals in beryllium-rich
granite pegmatites. It is composed of Beryllium silicate (Be2SiO4). Phenakite’
s hardness is ranked 7.5 to 8 on the Moh’s Scale with a Specific Gravity
of approximately 2.9 - 3.0. Its crystals are commonly vitreous and transparent,
however some translucent specimens have also been reported.
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Twinning is common in Phenakite’s
crystals and often results in penetration twins that appear to have a
second platy crystal growing into another crystal. The twins can look
like a normal crystal that has been folded. By far, this is the most interesting
form and highly favored among mineral collectors.
A rare mineral, Phenakite is commonly found in association with several
other gemstones such as Topaz, Cassiterite, Calcite, Hematite, Beryl (especially
Emerald), Chrysoberyl and Smoky Quartz. Its occurrence has been reported
at sites on the Takowaja River, Ural Mountains, Russia; Minas Gerias,
Brazil; Pala, San Diego Co., California; Mt. Antero and Pikes Peak, Colorado,
USA; and Norway.
Phenakite is quite a popular mineral for collectors, especially the twinned
crystal forms. It is sometimes cut as a gemstone. Although somewhat lacking
in color and fire, fine clear Phenakite crystals with good hardness can
make good choices for gemstones. Phenakite’s rarity also contributes to
its occasional use as a gemstone.
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