ALMANDINE

The Garnet
Group of
Minerals


GROSSULAR

ANDRADITE


RASBERRY GARNET
a variety of
GROSSULAR


UVAROVITE


GROSSULAR
on DIOPSIDE


MELANITE
a variety of
ANDRADITE


SPESSARTINE

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For natural garnet mineral specimens, select any of the mineral names above.

For Garnet Jewelry, see --> GARNET JEWELRY

Garnets as a group are relatively common in highly metamorphosed rocks and in some igneous formations. They form under the high temperatures and/or pressures that those types of rocks must endure. Garnets can be used by geologists as a gauge of how much temperature and pressure the rock has endured. As a gemstone, garnets have had a mixed reputation. Garnets do possess high indices of refraction, are hard enough, have pretty colors, are wonderfully transparent, lack cleavage and are durable; thus making good candidates for gemstones. However, 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. Garnets are greatly variable in colors and varieties, though, and many of these are both rare and beautiful, producing genuinely precious gemstones. Some garnets are truly unique in the mineral kingdom and have much to offer as both gemstones and mineral specimens. Of course, garnets are the January Birthstone.

The general formula for most of the garnets is A3B2(SiO4)3. The A represents divalent metals such as calcium, iron, magnesium and/or manganese. The B represents trivalent metals such as aluminum, chromium, iron and/or manganese and in the rarer garnets; vanadium, titanium, zirconium and/or silicon. The general formula for a couple of rarer garnets (hibschite and katoite) is A3B2(SiO4)3-X(OH)4X. The main differences in physical properties among the members of the garnet group are slight variations in color, density and index of refraction.

Garnets are isostructural, meaning that they share the same crystal structure. This leads to similar crystal shapes and properties. Garnets belong to the isometric crystal class, which produces very symmetrical, cube-based crystals. The most common crystal shape for garnets however is the rhombic dodecahedron, a twelve sided crystal with diamond-shaped (rhombic) faces. This basic shape is the trademark of garnets, for no other crystal shape is so closely associated with a single mineral group like the rhombic dodecahedron is with garnets. Most garnets are red in color, leading to the erroneous belief that all garnets are red. In fact a few varieties, such as grossular, can have a wide range of colors, and uvarovite is always a bright green. As a mineral specimen, garnets usually have well shaped and complex crystals and their color and luster can make for a very beautiful addition to a collection. At times, garnets are accessory minerals to other valuable and pretty gem minerals such as topaz, beryl, tourmaline, vesuvianite and diopside making these specimens extra special.

The Garnet Group is actually a larger group than most people realize. In the table below are the more common members with their chemistries and their significant divergent properties: density (SG), index of refraction (IR), and the typical color as well as their general environment of formation. Under environment of formation: metamorphic is indicated with an M and igneous with an I. All garnets may contribute to detrital sedimentary rocks but they are not of original sedimentary origin.


Mineral Name: Chemistry: Specific Gravity: Index of Refraction: Typical Color: Environment of
Formation:
ALMANDINE Fe3Al2(SiO4)3 SG = 4.3 IR = 1.83 reddish brown to brownM-schists & gneisses; I-pegmatites (rarely)
ANDRADITE Ca3Fe2(SiO4)3 SG = 3.8 IR = 1.89 brown, black or green M-serpentinites & skarns; I-volcanic
GROSSULAR Ca3Al2(SiO4)3SG = 3.5 IR = 1.75 colorless, orange or green M-contact marbles & serpentinites
PYROPE Mg3Al2(SiO4)3SG = 3.6 IR = 1.73dark red to ruby redM-serpentinites & gneisses; I-dunites & kimberlites
SPESSARTINE Mn3Al2(SiO4)3SG = 4.2 IR = 1.80orange, pink or brown M-gneisses & marbles; I-pegmatites & granites
UVAROVITE Ca3Cr2(SiO4)3SG = 3.8 IR = 1.86greenM-serpentinites

Other rarer members of the garnet group inlcude calderite, goldmanite, henritermierite, hibschite, katoite, kimzeyite, knorringite, majorite, morimotoite and schorlomite.

The mineral yafsoanite, a tellurate, the halide mineral cryolithionite, arsenate minerals berzeliite and manganberzeliite and the vanadate mineral palenzoaite share the same structure with the Garnet Group.


Much information for this page was provided from
Fleischer's Glossary of Mineral Species


See Our Garnet Specimens
Andradite
Almandine
Grossular
Spessartine
Uvarovite

Amethyst Galleries sells natural mineral specimens, including precious metals and gemstones. For a selection of Fine Jewelry, see our affiliates:

Garnet Jewelry - Hover over an item for more information
Round Red Garnet Sterling Silver Ring with Aquamarine - Venus Band
Scalloped shells form a fluted pattern on each side of this feminine tapered band, carefully handcrafted in your choice of gems and metals.Only $205.00 at Gemvara
no photoRound Red Garnet Sterling Silver Ring with Aquamarine - Venus Band
$205.00
Gemvara
Sterling Silver Ring with Sapphire & Red Garnet - Bamboo Two-Stone Ring
This double-gemstone bamboo ring makes a refined statement alone, or combines well with other bamboo rings.Only $175.00 at Gemvara
no photoSterling Silver Ring with Sapphire & Red Garnet - Bamboo Two-Stone Ring
$175.00
Gemvara
Round Red Garnet Sterling Silver Ring - Simply Round Solitaire
Less is more in this sleek solitaire ring with round brilliant-cut center. Delicate, feminine and simply stylish, this ring is perfect worn alone or stacked. Different stone sizes and band widths are available.Only $175.00 at Gemvara
no photoRound Red Garnet Sterling Silver Ring - Simply Round Solitaire
$175.00
Gemvara
Round Rhodolite Garnet Sterling Silver Ring with Red Garnet & Smoky Quartz - Venus Band
Scalloped shells form a fluted pattern on each side of this feminine tapered band, carefully handcrafted in your choice of gems and metals.Only $200.00 at Gemvara
no photoRound Rhodolite Garnet Sterling Silver Ring with Red Garnet & Smoky Quartz - Venus Band
$200.00
Gemvara
18.00ct t.w. Garnet, .25ct t.w. Diamond Necklace in Silver. 18"
Like a jeweled crown, this necklace will adorn your neck in ornate treasures. Blossoming shapes with .25 ct. t.w. diamonds drape across a rope chain with pear-shaped drops of 18.00 ct. t.w. garnets. Lobster clasp, sterling silver necklace. Garnet...Only $276.50 at Ross-Simons
no photo18.00ct t.w. Garnet, .25ct t.w. Diamond Necklace in Silver. 18"
$276.50
Ross-Simons
Round Amethyst Sterling Silver Ring with Green Tourmaline & Red Garnet - Sheltering Sky Ring
The sleek lines of this ring evoke an enfolding embrace. Set with birthstones, this style becomes a very fashionable mother-child ring.Only $305.00 at Gemvara
no photoRound Amethyst Sterling Silver Ring with Green Tourmaline & Red Garnet - Sheltering Sky Ring
$305.00
Gemvara
5.50ct t.w. Garnet, .13ct t.w. Diamond Drop Earrings in Silver
Dazzle any look with icy blocks of 5.50 ct. t.w. burgundy garnet gemstones with .13 ct. t.w. diamond accents. Hinged posts, sterling silver earrings. Garnet birthstones are the perfect gift for January birthdays.Only $87.50 at Ross-Simons
no photo5.50ct t.w. Garnet, .13ct t.w. Diamond Drop Earrings in Silver
$87.50
Ross-Simons
Round Peridot Sterling Silver Ring with Red Garnet - Venus Band
Scalloped shells form a fluted pattern on each side of this feminine tapered band, carefully handcrafted in your choice of gems and metals.Only $200.00 at Gemvara
no photoRound Peridot Sterling Silver Ring with Red Garnet - Venus Band
$200.00
Gemvara
Round Green Tourmaline Sterling Silver Ring with Red Garnet & Yellow Sapphire - Venus Band
Scalloped shells form a fluted pattern on each side of this feminine tapered band, carefully handcrafted in your choice of gems and metals.Only $205.00 at Gemvara
no photoRound Green Tourmaline Sterling Silver Ring with Red Garnet & Yellow Sapphire - Venus Band
$205.00
Gemvara
Round Green Tourmaline Sterling Silver Ring with Amethyst & Rhodolite Garnet - Split Bamboo Three-Stone Ring
The open band of this stylish ring cradles three brilliant bezel-set gems.Only $185.00 at Gemvara
no photoRound Green Tourmaline Sterling Silver Ring with Amethyst & Rhodolite Garnet - Split Bamboo Three-Stone Ring
$185.00
Gemvara
Round Rhodolite Garnet Sterling Silver Ring with London Blue Topaz & Iolite - Liana Ring with Three Gems
This lovely leafy vine ring twines across the finger while brilliant gems bloom among the leaves.Only $185.00 at Gemvara
no photoRound Rhodolite Garnet Sterling Silver Ring with London Blue Topaz & Iolite - Liana Ring with Three Gems
$185.00
Gemvara
Round Amethyst Sterling Silver Ring with Green Tourmaline & Red Garnet - Liana Ring with Three Gems
This lovely leafy vine ring twines across the finger while brilliant gems bloom among the leaves.Only $185.00 at Gemvara
no photoRound Amethyst Sterling Silver Ring with Green Tourmaline & Red Garnet - Liana Ring with Three Gems
$185.00
Gemvara
Round Fire Opal 14K Rose Gold Earrings with Red Garnet & Ruby - Halo Earrings
Classic yet dazzling, a halo of gemstone surrounds the center gems in a blaze of brilliance. These earrings are so perfectly simple you'll never take them off.Only $705.00 at Gemvara
no photoRound Fire Opal 14K Rose Gold Earrings with Red Garnet & Ruby - Halo Earrings
$705.00
Gemvara
Sterling Silver Ring with Red Garnet & Pink Tourmaline - Remember Forever Ring
Two gems wrapped in a knot to remember this moment forever.Only $155.00 at Gemvara
no photoSterling Silver Ring with Red Garnet & Pink Tourmaline - Remember Forever Ring
$155.00
Gemvara
2.84 TCW Marquise-Cut Garnet and Diamond Accent Ring in 10k Gold
The startling beauty of garnets and diamond accents. A superb example of a fashion-inspired look created with 2.84 carats T.W. of deeply colored garnets ignited by diamond accents. A 10k gold ring that's sure to be noticed. Sizes 5-10.Only $265.99 at PalmBeachJewelry
no photo2.84 TCW Marquise-Cut Garnet and Diamond Accent Ring in 10k Gold
$265.99
PalmBeachJewelry

Popular Members of the Silicates Class








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