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Goshenite is the
transparent, colorless, alkali-bearing pure beryl that was discovered
in Goshen, Hampshire County, Massachusetts. The Lily Pond mine in a pegmatite
near a small lake was the source of crystals accompanied by other pale
greenish-blue, bluish-green, yellowish, pink, and white beryl crystals.
Dr. John Sinkankas tells us that originally the designation included "pink
beryls" and "pale-colored beryls." The name is now applied to transparent
colorless beryls and often includes nearly colorless aquamarine, where
the blue tones are undetected. "Lucid" and "white" beryl are terms frequently
used by members of the jewelry industry to describe morganite. No trace
elements are present in the chemical make-up of goshenite to impart color.
Low dispersion (0.014) may contribute to the infrequent use of goshenite
as a desired gem, despite its excellent hardness, toughness, and resistance
to corrosive substances. Since the 1st century A.D., the good qualities
of colorless beryl have made it an ideal substitute for other colorless
gemstones. Silver or green foil is sometimes placed behind the faceted
colorless beryl and mounted in a "closed" setting to create imitations
of diamonds and emeralds. Doublets and triplets constructed by "sandwiching"
sections with colored cement or a thin slice of a synthetic or natural
gemstone are used to simulate other valuable gems. The slice of natural
gemstone could contain inclusions specific to the imitated gem. Bezel
mounts hide the junctures at the girdles of such creations and make the
substitution difficult to detect.
Beryl occurs in such quantities of large and often flawless crystals
that inclusions in goshenite used for gem purposes are seldom tolerated.
Goshenite is found worldwide, but significant deposits lie in various
locations in the former U.S.S.R., Mexico, Brazil, and Canada. California,
Colorado, Utah, Idaho, South Dakota, North Carolina, Maine, Connecticut,
and New Hampshire are all sources of goshenite in the United States.
Gemstone Properties
| Specie |
Aquamarine |
| Composition: |
beryllium aluminum silicate Be 3 Al 2 Si 6 O 18 |
| Class: |
silicate; cyclosilicate |
| Group |
beryl |
| Species: |
goshenite |
| Crystal System: |
hexagonal per Arem; hexagonal (trigonal) per Schumann |
| Variety: |
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| Colors: |
colorless |
| Phenomena: |
none |
| Streak: |
white |
| Diaphaneity: |
transparent, translucent to opaque |
| Habit: |
prismatic |
| Cleavage: |
imperfect; none |
| Fracture: |
conchoidal |
| Fracture Lustre: |
vitreous |
| Lustre: |
vitreous |
| Specific Gravity |
varies from 2.60 to 2.90 |
| Hardness |
7.50 to 8.0 |
| Toughness: |
very good; can be brittle |
| Refractive Index |
o=1.566 to 1.602; e= 1.562 to 1.594 |
| Birefringence: |
varies from 0.004 to 0.008 |
| Optic Character |
uniaxial negative |
| Dispersion: |
0.014 |
| Pleochroism |
none |
| Ultraviolet Fluorescence |
none |
| Spectra |
not usable |
| Color Filter |
no information |
| Aqua Filter |
no reaction; green indicates nearly colorless aquamarine |
| Chelsea Filter |
no information |
| Solubility |
insoluble in acids except in fluoric acid |
| Thermal Traits |
avoid thermal shock; remove stone during jewelry repairs |
| Treatments |
none |
| Inclusions |
no specific references to inclusions in goshenite were found |
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