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crystals,
gems and minerals
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Garnet
(January birthstone)
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Scientific:
Garnet is the name of a
family of chemically related minerals that
includes Almandine, Pyrope, Spessartine,
Grossular and Andradite. They can all be
found as gemstones with the Almandine Pyrope
type being the type most commonly used.
Because of their chemical compositions,
garnet occurs in most colors other than
blue. |
Garnet from Kunar, Afghanistan
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Uvarovite
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Most
garnets are all deep shades of red, except
for Uvarovite which is green. The blood red
color of pyrope is due to its iron and cro-chromium
content. It rarely has inclusions, but when
present they are rounded crystals or have
irregular outlines. Pyrope is found in
volcanic rock luster and alluvial deposits
and may, along with certain other minerals,
indicate the presence of diamond- bearing
rocks. Localities include the USA, South
Africa, Argentina, Australia, Brazil,
Myanmar, Scotland.
Garnets can be used by geologists as a gauge
of how much temperature and pressure the
rock has endured. Garnets are for the most
part, considered minor gemstones, and some
are not very valuable. Even though garnets
have pretty colors, are wonderfully
transparent, and are durable, thus making
them good candidates for gemstones, many
people consider garnets to be inferior to
other colored gems. This may be due to
garnet's relative abundance and widespread
use, and therefore a (typically) low price.
However, uvarovites, tsavorites, and
rhodolites are particularly valuable. |
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Hardness:
6.5 - 7.5
General garnet composition: A3B2(SiO4)3,
where Ca, Mg, Fe2+, or Mn2+ occupy the A
site, and the B site contains Al, Fe3+ or
Cr3+. Hydrous garnets may contain up to 8.5%
H2O.
Chemical Composition of Common End-member
Garnet Species
Pyralspite Garnet Group
Almandine: Fe3Al2(SiO4)3
Pyrope: Mg3Al2(SiO4)3
Spessartine: Mn3Al2(SiO4)3
Ugrandite Garnet Group
Andradite: Ca3Fe2(SiO4)3
Grossular: Ca3Al2(SiO4)3
Uvarovite: Ca3Cr2(SiO4)3
Less Common End-member Garnet Species
Calderite: Mn3Fe3+2(SiO4)3
Goldmanite: Ca3V2(SiO4)3
Hydrogrossular: Ca3Al2(SiO4)3-x(OH)4x
Hibschite: Ca3Al2(SiO4)3-x(OH)4x (where x is
between 0.2 and 1.5)
Katoite: Ca3Al2(SiO4)3-x(OH)4x (where x is
greater than 1.5)
Kimzeyite: Ca3(Zr,Ti)2[(Si,Al,Fe3+)O4]3
Knorringite: Mg3Cr2(SiO4)3
Majorite: Mg3(Fe,Al,Si)2(SiO4)3, discovered
in a meteorite!
Morimotoite: Ca3Ti4+Fe2+(SiO4)3
Schorlomite: Ca3(Ti4+,Fe3+)2[(Si,Ti)O4]3 |
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History:
"Garnet" may come from pomum granatum, Latin
for pomegranate. The gem color of the
Almandine Pyrope group is similar to that of
a pomegranate. Garnets have a long factual
and mythical history. They were popular for
jewelry in the 18th and 19th centuries. It
was a mark of distinction to use slices of
garnet in the windows of churches and
temples. Legend has it, that Noah suspended
a finely cut, glowing garnet to illuminate
the ark.
Myth:
In medieval times garnets
were thought to cure depression, protect
against bad dreams and relieve diseases of
the liver and hemorrhages. The Amazon women
were said to been empowered by the garnets
they wore on their breastplates. |
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Metaphysical:
Garnets are good for the
1st, or base, chakra. It is the stone of new
beginnings, especially because it is the
birthstone of January. This is a stone of
commitment and fidelity, especially for
women (this is one of the reasons it was so
popular in jewelry).
Wearing the red garnets, because they are
the color of blood, promotes good
circulation, especially in the lower half of
the body. Thus, they are also good for
fertility. They help promote passion between
lovers.
Wearing the green garnets promotes great
vitality and growth as well as attracting
abundance. |
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Teresa's Rock of the Week, formerly Gail's Rock of the Week |
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