Andradite Garnet Value, Price, and Jewelry Information

Andradite garnet: Stanley Butte, Arizona (ca 3 cts). Photo © Joel E. Arem, PhD, FGA. Used with permission.

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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.

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.

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.

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.

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.

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 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.

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.

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.

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 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.

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.

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.