Demantoid Garnet Value, Price, and Jewelry Information

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Modified square/cushion-cut demantoid garnet, 1.88 cts, 6.0 x 6.0 x 5.0 mm, Antetezambato, Ambanja District, Antsiranana Province, Madagascar. © Rob Lavinsky, www.iRocks.com. Used with permission.

One of the rarest garnet varieties, demantoid can have a green color that rivals emerald and a fire that exceeds diamond. Demantoids are highly prized by both gem collectors and jewelry enthusiasts.

Demantoid Garnet Value

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Almandine Garnet - Top Color: oR, R, PR, rP 6/4

All Sizes
Almandine
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Almandine/Pyrope Garnet Blend (Mozambique) - Red-Brown Colors

All Sizes
Mozambique
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Rhodolite (Almandine/Pyrope Blend) - Fine Color: rP, PR 6/5

.5 to 1 carat
Faceted
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Cabochons
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1 to 10 carats
Faceted
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Cabochons
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10 carats plus
Faceted
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Cabochons
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Andradite - Fine Color: G 5/4

All Sizes
Andradite
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Demantoid Garnet

to 1 carat
Demantoid
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1 to 3 carats
Demantoid
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Grossular Garnet

.5 to 1 carat
Mint Green (Merelani)
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Yellow/Orange
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Yellow/Green
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Other Colors
/ct
1 to 5 carats
Mint Green (Merelani)
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Yellow/Orange
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Yellow/Green
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Other Colors
/ct to /ct
5 carats plus
Mint Green (Merelani)
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Yellow/Orange
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Yellow/Green
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Other Colors

Hessonite Garnet - Fine Color: yO 4/5

All Sizes
Hessonite Garnet
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Tsavorite Garnet - Fine Color: G 6/5

.5 to 1 carat
Tsavorite
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1 to 2 carats
Tsavorite
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2 carats plus
Tsavorite
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Mali Garnet (Andradite/Grossular Blend)

All Sizes
Mali Garnet
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Malaya (Malaia) Garnets

.5 to 1 carat
Malaya (Malaia) Garnets
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1 to 5 carats
Malaya (Malaia) Garnets
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5 carats plus
Malaya (Malaia) Garnets
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Pyrope - Fine Color: R 6/5

1 carat plus
Pyrope
/ct

Chrome Pyrope

All Sizes
Chrome Pyrope
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Spessartite Reds

.5 to 3 carats
Little 3 Mine
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African
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Darker reds
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3 to 6 carats
Little 3 Mine
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African
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Darker reds

Mandarin Garnet - Orange - Fine Color: O 4/5

All Sizes
Mandarin Orange
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Uvarovite

10 carats plus
Druzy
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Star Garnet

All Sizes
4 Ray Star
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6 Ray Star
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Color Change Garnet

.5 to 1 carat
Africa
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United States
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1 to 6 carats
Africa
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United States
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Cabochons

All Sizes
Common Red to Purple
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View Almandine Garnet Profile

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Even with the discovery of new sources since the 1990s, demantoid remains very rare. It’s the most well-known andradite garnet and one of the most valuable garnets of any variety. Clean, facetable stones command very high prices per carat. However, demantoids with horsetail inclusions — wavy, golden, and fibrous — are especially coveted by collectors.

oval-cut demantoid - Russia

Brilliant, oval-cut demantoid with horsetail inclusions, 2.67 cts, 8.27 x 6.81 x 5.71 mm, Ural Mountains, Russia. © Rob Lavinsky, www.iRocks.com. Used with permission.

For more information on value and quality factors for demantoids, consult our buying guide.

Demantoid Garnet Information

Data Value
Name Demantoid Garnet
Is a Variety of Andradite
Crystallography Isometric
Refractive Index 1.881-1.888
Colors Yellow-green, green, deep green
Luster Adamantine
Hardness 6.5-7
Wearability Good
Fracture Conchoidal
Specific Gravity 3.82-3.88 (San Benito, CA demantoid: 3.81)
Birefringence None
Cleavage None
Dispersion 0.057
Heat Sensitivity Yes
Luminescence None
Luminescence Present No
Enhancements Heat treatment
Typical Treatments Heat Treatment
Transparency Transparent
Absorption Spectrum Strong band visible at 4430, cutoff at violet end of the spectrum. Chromium spectrum visible, with a doublet at 7010, sharp line at 6930, and two bands in orange at 6400 and 6220. Demantoid is red in the Chelsea filter.
Phenomena Occasional chatoyancy due to fibrous inclusions.
Birthstone January
Formula Ca3Fe2Si3O12, chromium (Cr) traces cause green color, ferric iron (Fe3+) traces cause yellow color.
Pleochroism None
Optics Isotropic. May show anomalous birefringence.
Etymology After the old German demant for “diamond.”
Occurrence Schists and serpentine rocks; metamorphosed limestones and contact zones.
Inclusions Horsetail inclusions of byssolite (fibrous amphibole) or chrysotile.
demantoids - faceted set

Demantoids: Russia (1.93, 0.93, 4.37). Photo © Joel E. Arem, PhD, FGA. Used with permission.

What is Demantoid?

Demantoid was discovered in Russia in the early 19th century. In 1854, the noted mineralogist Nils Gustaf Nordenskiöld identified this gem as a variety of andradite garnet. These stones had such exceptional brilliance and dispersion or “fire” that they inspired Nordenskiöld to name demantoid after its “diamond-like” appearance.

Does Demantoid Make a Good Jewelry Stone?

Demantoid Brooch Pendant

Demantoid and diamond brooch-pendant, Moscow (1899-1908), collection V. Kirichenko. Photo by Shakko. Licensed under CC By-SA 3.0.

In fact, demantoid has greater brilliance and a higher dispersion than its diamond namesake as well as other well-known green gemstones, such as emerald and peridot. Although dark body colors can mask their dispersion, small demantoids with light colors are quite dazzling.

Like most garnets, demantoids can make excellent jewelry stones. However, some demantoids may have a hardness of 6.5, somewhat lower than most other garnets. This means they’re somewhat susceptible to scratching. Therefore, use protective settings for these gems, especially if used as ring stones.

Demantoid was a popular gemstone during the Belle Époque period (1890-1915), especially in Art Nouveau jewelry. The Russian Czars particularly favored this gem.

Russia was long the only source of demantoids, but supplies ran so low, these gems were usually seen only in antique jewelry pieces. However, since the 1990s, new discoveries in Namibia, Madagascar, and other locations, as well as renewed mining in Russia, have made the gem more available. Today, demantoids are still desirable, but very expensive, jewelry stones.

3.80-ct demantoid - Namibia

3.80-ct demantoid, clarity VVSI, sourced near Karibib, Namibia. Photo © Claradyn Venter. Used with permission.

Do All Demantoids Have Horsetail Inclusions?

Horsetail inclusions of byssolite or chrysotile, usually golden in color, are named after their long, wavy appearance. These inclusions 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, nor do all demantoids have horsetails.

On very rare occasions, inclusions in demantoids may produce cat’s eye gems.

0.38-ct demantoid with horsetail inclusions - Russia

Russian demantoid with horsetail inclusions, 0.38 cts, 4.3 x 3 mm. Photo courtesy of liveauctioneers.com and Jasper52.

How to Tell a Demantoid from an Emerald

Although demantoids may have an emerald-like color and included appearance, the optical and physical properties of these two distinct gem species differ considerably. Most visibly, demantoids have greater dispersion and no birefringence. (Note that some demantoids may show anomalous birefringence. A polariscope examination can help determine if a stone is truly birefringent).

Demantoid Garnet Madagadcar

Garnet on matrix (demantoid variety), 2.8 x 2.4 x 1.5 cm, Madagascar. © Rob Lavinsky, www.iRocks.com. Used with permission.

How to Tell Demantoids from Other Green Garnets

Like demantoids, tsavorites and uvarovites are rare garnet varieties with emerald-like color. However, the specific gravity (SG) and dispersion of demantoid exceed that of its green garnet brethren.

Are There Synthetic Demantoids?

Demantoid hasn’t been synthesized, but green glass as well as green yttrium aluminum garnet (YAG), a synthetic garnet, have been used as simulants.

Demantoid Enhancements

Heating may improve demantoid color. This is a stable and undetectable treatment.

Where are Demantoids Found?

Historically and currently, Russia has been an important producer of demantoids. Notable gem sources include the Ural Mountains region, the Koryakskoe plateau, and the Kola Peninsula.

Since 1996 and 2009, respectively, Namibia and Madagascar have become commercially important sources.

2.15-ct demantoid - Namibia

2.15-ct demantoid, clarity IF, sourced near Karibib, Namibia. Photo © Claradyn Venter. Used with permission.

In Italy, Ala, Piedmont produces dark, apple-green material. Val Malenco, Sondrio Province also produces demantoids.

demantoids in asbestos matrix - Italy

This specimen features about a dozen demantoids on a fibrous asbestos matrix. The largest crystal measures about an inch across. 5.5 x 3.7 x 1.2 cm, Val Malenco, Sondrio Province, Lombardy, Italy. © Rob Lavinsky, www.iRocks.com. Used with permission.

Other notable sources of gem-quality demantoids include the following:

  • Afghanistan; Azerbaijan; Canada; Democratic Republic of the Congo; Iran; Mexico; Pakistan; South Korea; Sri Lanka; San Benito County, California, United States.
demantoid - Iran

Andradite (variety demantoid), 3.0 x 2.7 x 2.4 cm, Belqeys Mountain, near Takab, West Azerbaijan, Iran. © Rob Lavinsky, www.iRocks.com. Used with permission.

Stone Sizes

Demantoids are typically small stones. Stones larger than 10 carats are very rare. Faceted stones greater than 1 carat are rarely seen. The largest demantoid ever found hailed from the Russian Urals and weighed 252.5 carats or 50.5 grams.

The Smithsonian Institution has a faceted 11.24-carat specimen on display.

trilliant-cut demantoid - Madagascar

Modified trilliant-cut demantoid, 2.03 cts, 12.0 x 9.0 mm, Antetezambato, Ambanja District, Antsiranana Province, Madagascar. © Rob Lavinsky, www.iRocks.com. Used with permission.

Demantoid Trade Names

Consumers may encounter demantoids offered for sale under such names as “Siberian emeralds,” “Siberian chrysolites,” and “Ural chrysolites.” Of course, garnets constitute a distinct group of gem species from emeralds. “Chrysolite” is an archaic term for green to yellow-green gems that has been applied to peridots as well as chrysoberyls and prehnites. These gems also constitute species distinct from demantoids.

For more examples, consult our article on false or misleading gemstone names.

Demantoids - Russia

Demantoids from the Bobrovka River, Russia, on display at the Mineralogical Museum, Bonn, Germany. Photo by Elke Wetzig. Licensed under CC By-SA 3.0.

How to Care for Demantoids

Heat sensitive garnets, like demantoids, should be cleaned with warm water, detergent, and a soft brush. Avoid mechanical cleaning and exposure to extreme heat.

Consult our gemstone care guide and jewelry cleaning guide for more information.

Antique beetle pin - demantoids. red garnets, and diamonds

This antique beetle pin, circa 1870, features demantoids and diamonds, red garnets for the eyes, and unparalleled 14k craftsmanship. Russian demantoids ~ 0.25-0.50 cts. Photo © Joel E. Arem, PhD, FGA. Used with permission.

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