Andradite Garnet Value, Price, and Jewelry Information


brilliant-cut andradite - Mexico
Golden brown, brilliant-cut andradite, 3.07 cts, 8.9 mm, Mexico. Photo courtesy of liveauctioneers.com and Heritage Auctions.

Andradite is one of the most sought after garnet species. Although more sources have been discovered in recent decades, gem-quality andradites remain rare.

Andradite Value

Demantoid garnet, the chromium-bearing, green variety of andradite, is the most well-known and valuable andradite. For more information on value and quality factors for this gem, consult our demantoid buying guide.

round brilliant-cut demantoid andradite garnet - Russia
Round brilliant-cut demantoid with horsetail inclusions, 0.87 cts, 5.7 mm, Russia. © The Gem Trader. Used with permission.

For more information on value and quality factors for andradites and other garnets in general, consult our garnet buying guide.

round faceted andradite
Round andradite garnet, 6.06 cts, 11.4 x 11.43 x 6.87 mm. Photo courtesy of liveauctioneers.com and Heritage Auctions.

The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.

Garnet Value via Gem Price Guide
Top Color: oR, R, PR, rP 6/4
Almandine All sizes
to /ct
Fine Color Andradite: G 5/4
Andradite All sizes
to /ct
Chrome Pyrope All sizes
to /ct
Color Change .5 to 1 carat 1 to 6 carats
Africa to /ct to /ct
US to /ct to /ct
Demantoid to 1 carat 1 to 3 carats
to /ct to ,000/ct
Grossular Garnet .5 to 1 carat 1 to 5 carats 5 carats plus
Mint Green (Merelani) to /ct to /ct to /ct
Yellow/Orange to /ct to /ct to /ct
Yellow/Green to /ct to /ct to /ct
Other colors /ct /ct to /ct
Fine Color Hessonite: yO 4/5
Hessonite Garnet All sizes
to /ct
Malaya Garnet .5 to 1 carat 1 to 5 carats 5 carats plus
to /ct to /ct to /ct
Mozambique All sizes
to /ct
Mali Garnet All sizes
to /ct
Fine Color Spessartite: O 4/5
Mandarin Orange All sizes
to /ct
Fine Color Pyrope: R 6/5
Pyrope 1 carat plus
/ct
Fine Color Rhodolite: rP, PR 6/5
Rhodolite .5 to 1 carat 1 to 10 carats 10 carats plus
Faceted to /ct to /ct to /ct
Cabochons to /ct to /ct to /ct
Spessartite Reds See Mandarin above .5 to 3 carats 3 to 6 carats
Little 3 Mine to /ct to /ct
African to /ct to /ct
Darker reds to /ct
Star Garnet All sizes
6 ray star to /ct
4 ray star to /ct
Fine Color Tsavorite: G 6/5
Tsavorite .5 to 1 carat 1 to 2 carats 2 carats plus
Faceted to /ct to /ct to ,000/ct
Uvarovite 10 carats plus
Druzy to /ct
Cabochons All Sizes
Common red to purple to /ct

See the entire Gem Price Guide.

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Andradite Information

DataValue
NameAndradite
Is a Variety ofGarnet
VarietiesDemantoid, Melanite, Topazolite
Crystallography Isometric
Refractive Index 1.855-1.95
Colors Green, yellowish green, yellow, brown, brownish red, black. May rarely show color zoning.
Luster Vitreous to resinous.
Fracture Conchoidal
Hardness 6.5-7
Specific Gravity 3.70-4.10; melanite about 3.9; demantoid 3.82-3.88.
Birefringence None.
Cleavage None
Dispersion 0.057
Heat SensitivitySome
Luminescence None
Enhancements Heat (demantoid)
Transparency Translucent to transparent.
Absorption Spectrum A strong band is visible at 4430, cutoff at the violet end of the spectrum. Sometimes (in demantoids) the Cr spectrum is visible, with a doublet at 7010, sharp line at 6930, and 2 bands in the orange at 6400 and 6220. Demantoid is red in the Chelsea filter.
Phenomena Chatoyancy, iridescence (rare for andradites); color change (rare for andradite-grossular series garnets).
Birthstone January (Garnet).
FormulaCa3Fe2Si3O12
Pleochroism None.
Optics Isotropic, may show anomalous birefringence. N = 1.88-1.94; demantoid: 1.881-1.888; topazolite (yellow): 1.887; melanite: 1.89.
EtymologyAndradite is named after the Brazilian mineralogist, José Bonifácio de Andrada e Silva, who described one of the sub-varieties of this garnet species. “Colophonite” comes from its resemblance to colophony or rosin, a plant resin. “Demantoid” comes from the old German demant for “diamond,” due to its high dispersion. “Melanite” comes from the Greek melanos for “black.” Topazolite is named after its resemblance to yellow topaz.
OccurrenceAndradite occurs in schists and serpentine rocks (demantoid and topazolite); also in alkali-rich igneous rocks (melanite); and in metamorphosed limestones and contact zones (brown and green colors).
Inclusions So-called horsetail inclusions of byssolite (fibrous amphibole) or chrysotile in demantoids (but see “Identifying Characteristics” below). Curved fibers (not necessarily “horsetails”), single-phase (hollow tubes) and two-phase inclusions, fingerprints, crystals.
andradite garnet - faceted and rough - Arizona
Andradite garnet: Stanley Butte, Arizona (ca 3 cts). Photo © Joel E. Arem, PhD, FGA. Used with permission.

Comments

Andradites have a higher dispersion than any other variety of garnet. It even exceeds that of other well-known jewelry stones, such as diamonds. While dark body colors may mask their “fire,” light colors, especially in small gems, can be dazzling.

Andradites can occur in a wide range of colors: green, yellowish green, yellow, brown, brownish red, and black. While rare, color zoning may occur, such as red/brown, brown/orange/green, and even red/green.

bi-colored andradite - emerald cut
This unusual garnet is definitely an andradite but it’s bi-colored green and red. For more information on this particular gemstone and its GIA analysis, see this article. 2.71 cts, emerald cut. © All That Glitters. Used with permission.

The following are the andradite varieties and series most likely to be encountered either as faceted gems or mineral displays.

Demantoid

The most well-known andradite variety, demantoids can combine rich, emerald-like green color with exceptional dispersion and brilliance. They receive their green color from chromium (Cr) traces, while ferric iron (Fe3+) traces may add yellow color. These rare gems are always in high demand and may be the most valuable of any garnet variety.

See our separate demantoid garnet gem listing for more information.

Topazolite

These yellow to yellowish green andradites are even rarer than demantoids, especially as facetable material. As a result, they’re less well-known and encountered more rarely in jewelry.

andradite variety topazolite gems - Russia
Matched topazolite garnets, 1.19 ctw, 5.1 mm, round brilliant cuts, Russia. © The Gem Trader. Used with permission.

The name refers only to a color similarity with classic yellow topazes. Garnets and topazes are distinct gem species.

andradite crystals - topazolite variety - Madagascar
Large (up to 3.5 cm across), olive-green to cognac-colored topazolite garnets in matrix, Antetezambato, Ambanja District, Diana Region, Antsiranana Province, Madagascar. © Rob Lavinsky, www.iRocks.com. Used with permission.

Melanite

These andradites contain 1-5% titanium oxide and have black color. They can show a near adamantine (diamond-like) surface luster, thus making them very reflective.

andradite crystal - melanite variety - Mexico
Melanite crystal, 2.4 x 2.2 x 1.9 cm, Chihuahua, Mexico. © Rob Lavinsky, www.iRocks.com. Used with permission.

Historically, melanites have been used for mourning jewelry. They also make fine accent stones.

andradite side stones - melanite variety - silver ring
Sterling silver ring with a gray pearl, cubic zirconias, and melanites. The melanites measure 1.55 mm each. Photo courtesy of liveauctioneers.com and Jasper52.

Iridescent Andradite

Andradites with strong, multi-colored iridescence have been found in Mexico, the southwestern United States, and Japan. This material, especially that from Japan, has been called “rainbow garnet.”

iridescent andradite - "rainbow garnet" - Japan
Iridescent andradite garnet, freeform cabochon, 10.9 x 8.9 mm. Japan. © The Gem Trader. Used with permission.

Colophonite

This granular variety of andradite, usually brown, reddish, or orangish, has a resinous, amber-like luster.

andradite crystals - colophonite variety - New York
Colophonite on wollastonite, Willsboro, Essex County, New York. Photo by Dave Dyet. Public Domain.

Andradite-Grossular Garnet

Mali garnets are a blend of andradite and grossular species. They show dispersion and colors like andradites but have somewhat greater wearability, with a higher hardness and no heat sensitivity.

grossular-andradite blend - Mali garnet - pear cut
Pear-cut Mali garnet, 1.46 cts, treated gem. Photo courtesy of liveauctioneers.com and Collector’s Liquidation.

Some Mali garnets may show a color change effect, from grayish green in fluorescent light to brown in incandescent light.

Andradite-Schorlomite Garnet

Schorlomite, a titanium-rich variety of garnet (N = 1.935), can form a series with andradite, which creates dark-colored stones, generally black, brown, or reddish brown. Like melanite, schorlomite occurs in alkali-rich igneous rocks.

Identifying Characteristics

The golden horsetail inclusions of demantoid garnets are some of the most well-known and celebrated variety of gemstone inclusions. Gem collectors and jewelry aficionados prize them so much that gem cutters may even facet these stones to feature them. These inclusions may also cause a cat’s eye effect in some stones.

Horsetails have long been considered diagnostic for identifying demantoids. However, a 2018 study found horsetail inclusions in non-demantoid (brown) andradite. Thus, horsetails may not be sufficient in and of themselves for identifying demantoids.

andradite - horsetail inclusions in demantoid - Russia
This closeup of a Russian demantoid shows horsetail inclusions spreading from a chromite crystal within the gem. © The Gem Trader. Used with permission.

Many varieties of garnets show colors like those of andradites, and most garnets contain blends of multiple species. Therefore, distinguishing garnet varieties can be difficult. This chart comparing the refractive indices (RI), range of colors, and absorption spectra of different garnet species may help.

Uvarovites and tsavorites have demantoid-like (or emerald-like) green color. However, the specific gravity (SG) of demantoid exceeds that of these other rare and deep-green garnets.

Synthetics

Scientists have synthesized andradites for research into their physical and optical properties, such as their heat capacity and optical absorption. However, there’s no known jewelry use for this lab-created material. 

Enhancements

Demantoid garnets may receive heat treatments to lighten their color and remove brown tones. 

Sources

There are many sources of andradite across the globe, but gem-quality supplies are limited.

In 2009, a mine near Antetezambato, Madagascar emerged as a notable source of fine, gem-quality demantoid and topazolite.

andradite crystal - Madagascar
Andradite crystal on matrix. Antetezambato, Ambanja District, Diana (Northern) Region, Antsiranana Province, Madagascar. Photo by Géry Parent. Licensed under CC By-SA 3.0.

Russia has produced fine demantoids as well as topazolites and some (small) brown andradites.

Italy produces many varieties of andradite. Ala, Piedmont, yields dark apple-green demantoids and yellow to yellowish green topazolites. Val Malenco, Sondrio Province is also a notable source of demantoid. Monte Somma, Vesuvius, and Trentino produce melanite.

In the United States, San Benito County, California has produced a variety of gem-quality andradites: topazolite (N = 1.855-1.877, SG = 3.77-3.81), demantoid (N = 1.882, SG = 3.81), melanite, and an unusual cat’s eye material. Other US sources include the following: Arizona; Arkansas; Colorado; New Jersey; New Mexico (in metamorphic limestones and ore deposits); Pennsylvania. 

Other notable sources include the following:

  • Afghanistan; Australia; Canada; China; Democratic Republic of the Congo; Greenland; Iran; Japan; Mali; Mexico; Namibia; Norway; Pakistan; Peru; South Africa; South Korea; Sri Lanka; Sweden; Turkey; Uganda; Yemen; Zimbabwe.
andradite crystals - Peru
Andradites on matrix, up to 1” thick, Rosario Mabel claim, Pampa Blanca, Castrovirreyna Province, Huancavelica Dept., Peru. © Rob Lavinsky, www.iRocks.com. Used with permission.

Stone Sizes

Russia holds many fine demantoids in museum collections.

A collector in California owns a huge, green topazolite crystal, around 1 ounce in weight, that would yield faceted gems over 20 carats.

  • Smithsonian Institution (Washington, DC): 10.4 (Russia); also 4.1, 3.4, and 2.3.
  • Private Collection: 18 (sold in New York City).

Care

Like most garnets, andradites makes good jewelry stones, especially for engagement rings. However, most garnets are also heat sensitive, and andradites can contain crystal and liquid inclusions as well. Therefore, never clean them with ultrasonic cleaners or steamers since the stones may shatter. Instead, use warm water, mild detergent, and a soft brush.

Some andradites may have a hardness of 6.5, which means they are somewhat susceptible to scratching. Use protective settings for these gems.

For more recommendations, consult our gemstone jewelry care guide.

oval-cut andradite
Grayish yellow-green andradite garnet, oval modified brilliant cut, 1.94 cts, 8.46 x 6.43 x 4.38 mm. Photo courtesy of liveauctioneers.com and Dan Morphy Auctions.