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| Heliodor |
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| Heliodor |
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The yellow form of beryl, the
“mother of gemstones”
is known as Heliodor. It may also
appear in yellow, yellow-green,
orange and brown colors. However
Heliodor does not include golden
colors, as those are known as
golden beryl.
Beryl
occurs in a variety of colors,
but only the transparent ones
are used as gemstones. As pure
beryl is colorless, the traces
of the different impurities are
responsible for this gemstone’s
vast color range.
Some well-known colored gemstones
that belong to the beryl group
are emerald, morganite, goshenite,
bixbite and aquamarine. Whereas
the other forms of beryl are simply
referred to by their color (i.e.
golden beryl, red beryl etc.).
Heliodor
has a hardness of 7.5 - 8, a refractive
index of 1.57 - 1.60 and a hexagonal
crystal system. They are available
as both a faceted gem and as Heliodor
Cats Eye. Beryl (Heliodor) is
famous for its perfect, six-sided
prismatic hexagon crystals that
usually occur individually. Some
well-crystallized 8-meter forms
are also known to have existed.
Treating
the stone with oil can mask the
internal flaws in Heliodor and
thus one must be cautious of dealers
who often apply this treatment
to a stone without informing the
buyer. All varieties of Beryl,
including Heliodor can be faceted
into various gem cuts. Some stones
even display cat’s eye effect
when cut and polished. Transparent
beryl such as Morganite and Heliodor
are also carved sometimes into
ornamental figures. Perfect, transparent,
six-sided rough Heliodor crystals
are also worn occasionally as
pendants.
Heliodor
is found in Madagascar, Brazil,
Rangoon, Tien-Shan Mountains,
Tajikistan, Middle Eastern countries,
North Carolina and California
in the U.S.
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| Hemimorphite |
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| Hemimorphite |
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Formed from Hydrated Zinc Silicate
Hydroxide (Zn4 Si2 O7 (OH)2 -H2O),
Hemimorphite is found in a range
of colors such as green, blue-green,
white, colorless, brown and yellow.
Though it was originally named 'Calamine',
after its discovery in 1853, it
was renamed Hemimorphite after its
hemimorphic (meaning 'half shape')
crystal structure.
With
its high Zinc concentration, Hemimorphite
is also commonly used as a source
of the minor ore of zinc. Hemimorphite
has a hardness of 5 on the Moh's
scale and a Specific Gravity of
3.4. It is found in association
with Hydrozincite, Limonite, Aurichalcite,
Calcite and Smithsonite and occurs
as veins and beds in calcareous
rocks. Originally discovered in
Romania, Hemimorphite is found in
notable amounts in Santa Eulalia,
Mapimi (Mexico), New Mexico, New
Jersey (USA), England and Zambia.
Hemimorphites
are found in two distinct crystal
forms. One form produces a blue
to blue-green crust and the other
form is a glassy, clear or white,
thin crystal, which is prominently
displayed in nearly all mineral
museums around the world. Thus both
the forms are a must in the collection
of a serious mineral collector.
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| Hauyne |
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| Hauyne |
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Hauyne is sometimes called Huaynite.
It was discovered in 1807 on Mt Somma,
among Vesuvian lavas, Italy by the
French crystallographer, Mr. R. J.
Hauy (1743-1822), and was named after
him. The mineral has been found in
a typically beautiful electric blue
as well as green, red, yellow, and
gray colors.
It
is formed from Sodium Calcium Aluminum
Silicate Sulfate [(Na, Ca) 48Al6Si6(O,
S) 24(SO4, Cl) 1-2]. It has a hardness
of 5 - 6 on the Moh’s Scale
with a Specific Gravity of 2.4 -
2.5. Its crystals are vitreous and
can be sub-transparent to translucent,
often occurring as well-formed coarse
sized crystals. Hauyne belongs to
the Sodalite mineral group.
The
Sodalite group is also a group within
a group. Its members are also part
of a larger group called the Feldspathoids,
which are low-silica igneous minerals.
Other members of the Sodalite group
of minerals are Sodalite, Nosean,
Lazurite and Hackmanite. As it is
quite rare and has beautiful color,
Hauyne is highly priced.
Huayne
naturally occurs in igneous rocks
low in silica and rich in alkalies
such as volcanic rocks, which provide
the chemical supply and the environment
needed for the mineral to form.
Apart from Mt Somma, Italy, occurrences
of Hauyne have also been reported
in Tasmania, Australia, and in Eifel
and Schwarzwald in Germany.
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| Hiddenite |
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| Hiddenite |
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Hiddenite is quite a rare gemstone.
It has an unusual green color that
is unlike either Peridot or Emerald.
It was discovered in 1800 in Hiddenite,
a city in Alexander County, North
Carolina. Both the city and the
gem mineral were named after William
Earl Hidden, a mineralogist and
mining director from Newark.
Hiddenite is formed from Lithium
Aluminum Silicate (LiAlSi2O6). It
ranks 6.5 on the Moh’s Scale
of Hardness with a Refractive Index
of 1.66. The crystals are vitreous
and can be in either transparent
or translucent forms. For many years,
occurrence of Hiddenite was limited
to only North Carolina, however
new desposits were recently discovered
in Madagascar and Brazil.
It is used as both a collecting
specimen and as a gemstone. Due
to its cleavage, splintery fracture
and strong pleochroism, Hiddenite
requires skill and expertise to
cut and facet. The top and bottom
of the crystal reveal the deepest
colors and knowledgeable gem cutters
take advantage of this effect to
produce the finest quality Hiddenite.
Hiddenite is one of two varieties
of Spodumene. The other is Kunzite,
a pink to lilac variety. Kunzite
is the more common of the two and
and is better known by most gemstone
collectors. Kunzite has a lovely
pink to lilac color that is unique
in the gem kingdom. The green color
of Hiddenite ranges from a yellowish
to a bluish green. The gemstone
is strongly pleochroic meaning that
it can change color when viewed
from different angles, thus a gem
cutter must take care to orient
the stone in the best position for
the deepest color.
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