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Tanzanite
Diopside: Diopside is a very common mineral with worldwide
occurrence, and is related to jadeite. The color is
usually green, but may be to dark in shade. The hardness
is only 5-6 and the easy cleavage prevents its widespread
use as a faceted gem. Color varieties with al names
include malacolite (pale green), alaite (colorless),
and violane (massive violet).
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Gem
crystals come from Austria, Italy, New , Ontario, and
Switzerland. Burma and India produce massive green or
black material that has metallic-looking inclusions.
Cabochons cut from this material display cat's-eyes
or four-rayed stars. Both faceted and cabochon varieties
are inexpensive. |
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Enstatite
: Related to Diopside, spodumene, and jadeite, Enstatite rarely
.- in transparent crystals from which brown or green gems
can be These are usually very dark, with a hardness of 51/2
on the Mohs - Attractive green Enstatite suffer from easy
cleavage and poor toughness and are therefore collector stones,
but low in price. Star Enstatite are fairly common. Localities
include South Africa, Burma, and India..
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Tanzanite |
| Tanzanite
Euclase:
An attractive gem material, Euclase could bean
important gem 'or its scarcity and perfect cleavage.
The color range is colorless to :flue, yellowish-green,
pale yellow, and violet.
Blue stones are the - popular, and the hardness
of 71/2 allows them to be worn. Gems weighing
more than two to three carats are rare and can
be expensive. localities include Brazil and Tanzania.
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Fluorite:
This common mineral occurs throughout the world
in fine many of which are large and transparent.
Colors include white, yellow brown, green, violet,
and blue, but the hardness is only 4 and fluorite
cleaves readily. Faceted gems cannot be worn without
risk, but - e fluorite, sometimes called "blue
john," has been widely used ,for carvings
and ornamental purposes. |
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The
refractive index of 1 .43 is . the lowest of any gem material,
but attractive stones can still be -sometimes of more than
100 carats. Green fluorite sometimes ~ in carved form for
pale emerald, but the hardness eventually -reveals its identity.
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