ALMANDINE

The Garnet
Group of
Minerals


GROSSULAR

ANDRADITE


RASBERRY GARNET
a variety of
GROSSULAR


UVAROVITE


GROSSULAR
on DIOPSIDE


MELANITE
a variety of
ANDRADITE


SPESSARTINE

  Like: Share:  

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
Ross-Simons 1.30ct t.w. Citrine Koi Ring, Diamonds, Garnets in Silver
This flamboyant 1.30 ct. t.w. citrine koi ring with garnets and diamond accents will be perfect to express your love of water! Ideal for the aqua-lover on your shopping list, too. Sterling silver ring. Citrine birthstones are the perfect gift for...Only $225.00 at Ross-Simons
no photoRoss-Simons 1.30ct t.w. Citrine Koi Ring, Diamonds, Garnets in Silver
$225.00
Ross-Simons
Garnet & Diamond Semi-Eternity Channel Ring 14k White Gold (0.40ct)
Six red garnets are beautifully alternating with six brilliant-cut round diamonds. The stones have been elegantly set in a 14kt white gold channel setting, and are circling halfway around this semi-eternity band. This January birthstone ring is also...Only $565.20 at Allurez.com
no photoGarnet & Diamond Semi-Eternity Channel Ring 14k White Gold (0.40ct)
$565.20
Allurez.com
Ross-Simons 1.60 ct. t.w. Garnet Dangle Earrings in 14kt Yellow Gold
Fiery garnets of 1.60 ct. t.w. are framed in rope-edged and bead-detailed 14kt yellow gold. Leverbacks. Earrings measure approximately 1/4" in width and have a hanging length of 3/4". Garnet birthstones are the perfect gift for January birthdays.Only $187.50 at Ross-Simons
no photoRoss-Simons 1.60 ct. t.w. Garnet Dangle Earrings in 14kt Yellow Gold
$187.50
Ross-Simons
Half-Eternity Pave-Set Garnet Stacking Ring Palladium (0.95ct)
Wonderfully crafted in hypoallergenic palladium, this pave-set January birthstone ring features 17 garnets. This half-eternity natural garnet ring displays colored gemstones totaling in 0.95ct. Wear this fancy designer jewelry piece as a fashion ring,...Only $511.00 at Allurez.com
no photoHalf-Eternity Pave-Set Garnet Stacking Ring Palladium (0.95ct)
$511.00
Allurez.com
Ross-Simons 1.60 ct. t.w. Multi-Stone Eternity Band in Sterling Silver
This 1.60 ct. t.w. multi-stone eternity band is a rainbow of delight. A dream-come-true for jewelry lovers, it features round blue topaz, amethyst, garnet, peridot and citrine gemstones in a chic bezel-set design. Sterling silver ring. Peridot...Only $70.00 at Ross-Simons
no photoRoss-Simons 1.60 ct. t.w. Multi-Stone Eternity Band in Sterling Silver
$70.00
Ross-Simons
Naga Men's Dragon-Head Bracelet - John Hardy
Men's bracelet from the John Hardy Naga Collection. Black garnet stones. Blackened sterling silver dragon-head clasp. Handcrafted in Bali. About this collection: The Naga dragon symbolizes everlasting love and prosperity. According to Balinese legend...Only $495.00 at Neiman Marcus
no photoNaga Men's Dragon-Head Bracelet - John Hardy
$495.00
Neiman Marcus
Batu Chain Gold-Plate & Silver Coin Ring - John Hardy
From the John Hardy Classic Chain Collection. Sterling silver and oxidized sterling silver with signature Chain detail. Garnet set in 18-karat yellow gold-plated bezel. Coin detailed face. Open square station on shank. US ring size 7. Handmade in Bali....Only $495.00 at Neiman Marcus
no photoBatu Chain Gold-Plate & Silver Coin Ring - John Hardy
$495.00
Neiman Marcus
Garnet & Dark Horn Drop Earrings - Ashley Pittman
Ashley Pittman earrings offer a one-of-a-kind sensibility-these faceted garnet and dark horn drops were crafted by the hands of a local Kenyan artisan. Bronze. Faceted garnet. Polished dark horn spike drop. French wire backs. 2 3/4inL. Handcrafted in...Only $395.00 at Neiman Marcus
no photoGarnet & Dark Horn Drop Earrings - Ashley Pittman
$395.00
Neiman Marcus
White Garnet Heart Ring with Diamonds 1.43 Carat (ctw) in 10K White Gold
Garnet Heart Ring with Diamonds 1.43 Carat (ctw) in 10K White Gold #08JP68972GAW. Three heart shaped garnet gemstones imbue this riveting white gold heart ring, additionally housing an arrangement of sparkling diamonds. View item video above. SKU:...Only $249.00 at MyJewelryBox.com
no photoWhite Garnet Heart Ring with Diamonds 1.43 Carat (ctw) in 10K White Gold
$249.00
MyJewelryBox.com
Sterling Silver CZ, Garnet Ring Jewelry
This Ring was handmade by a master artisan and is one of a kind.Only $91.49 at JeGem.com
no photoSterling Silver CZ, Garnet Ring Jewelry
$91.49
JeGem.com
Sterling Silver Garnet Solitaire Ring Jewelry
This Ring was handmade by a master artisan and is one of a kind.Only $89.24 at JeGem.com
no photoSterling Silver Garnet Solitaire Ring Jewelry
$89.24
JeGem.com
Ross-Simons 3.35 Carat Garnet Ring With Diamonds in Sterling Silver
Deep jewel tones of purple captivate in this 3.35 carat oval garnet ring. Color comes to light with the diamond accents. Polished sterling silver ring. Garnet birthstones are the perfect gift for January birthdays.Only $140.00 at Ross-Simons
no photoRoss-Simons 3.35 Carat Garnet Ring With Diamonds in Sterling Silver
$140.00
Ross-Simons
Ross-Simons 1.60 ct. t.w. Garnet Eternity Band in 14kt White Gold
Red is the color of passion! This eternity band hosts a neverending circle of deeply hued 2.40 ct. t.w. garnet rounds. Carat weights vary by size. 14kt white gold ring. Garnet birthstones are the perfect gift for January birthdays.Only $335.00 at Ross-Simons
no photoRoss-Simons 1.60 ct. t.w. Garnet Eternity Band in 14kt White Gold
$335.00
Ross-Simons
Garnet Circle-Link Pave Bracelet With Diamond Accent In 18k Gold-Plated
Rated by 25,000+ Customers. Garnet Circle-Link Pave Bracelet With Diamond Accent In 18k Gold-PlatedOnly $66.49 at PalmBeachJewelry
no photoGarnet Circle-Link Pave Bracelet With Diamond Accent In 18k Gold-Plated
$66.49
PalmBeachJewelry
Ross-Simons 5.25 Carat Oval Garnet and Diamond Ring in 14kt Yellow Gold
So simple, it's brilliant. So elegant, it's a must-have. Our fabulous oval garnet ring features a 5.25 carat garnet gemstone and a border of .10 ct. t.w round brilliant diamonds. A lovely deep burgundy presentation, this 14kt yellow gold ring is from...Only $595.00 at Ross-Simons
no photoRoss-Simons 5.25 Carat Oval Garnet and Diamond Ring in 14kt Yellow Gold
$595.00
Ross-Simons

Popular Members of the Silicates Class








s


 


Copyright ©1995-2012 by Amethyst Galleries, Inc.
Site design & programming by galleries.com web services