Skip to content


Your cart is empty

Article: Demantoid


General Information and Characteristics of Demantoid

  • Demantoid is the green gemstone variety of the mineral andradite, a member of the garnet group of minerals.
  • The chemical formula of demantoid is Ca(SiO) with chromium substitution causing the green color.
  • It has a hardness of 6.5-7.0 on the Mohs scale.
  • The specific gravity of demantoid is 3.84.
  • Demantoid has an adamantine luster and a refractive index of 1.880-1.889.
  • Demantoid is always primarily green, ranging from a strong yellowish green to nearly the color of a fine emerald.
  • Some stones may have a brownish cast due to iron impurities.
  • Demantoid has a high dispersion, visible as rainbow-colored flashes of light.
  • The luster of demantoid is adamantine.
  • Finished demantoid stones are generally under 1 carat, with stones over 2 carats being rare.

History of Demantoid

  • Demantoid was discovered in 1868 in Russia's Ural Mountains.
  • The gem material was found in an alluvial deposit near the village of Elizavetinskoye.
  • Miners compared demantoid to diamond due to its high brilliance and dispersion.
  • Demantoid became popular in Russia and was used in jewelry by Peter Carl Fabergé.
  • In the 1970s and 1980s, more stones were found in the Bobrovka River, and limited production occurred in the central Ural Mountains around 1999.

Horsetails in Demantoid

  • Russian demantoids often contain horsetail inclusions of chrysotile, a type of asbestos.
  • Horsetail inclusions are feathery golden threads that resemble the tail of a horse.
  • These inclusions are diagnostic for natural demantoid and are not found in any other green gemstone.
  • Horsetails are regarded as desirable features in demantoid, indicating prestigious Russian origin.
  • Some demantoids from other locations may also contain horsetails, characteristic of a serpentinite origin.

References and Resources for Demantoid

  • Idar-Oberstein is a source of demantoid.
  • Shipley's Dictionary of Gems and Gemology provides information on demantoid.
  • The Gemological Institute of America (GIA) has grading reports and research resources on demantoid.
  • The International Gem Society offers information on demantoid garnet value, price, and jewelry.
  • Various articles and studies published in Gems & Gemology provide insights into demantoid, including its inclusions and origins.

Importance and Value of Demantoid

  • Demantoid is highly sought after by collectors and gemstone enthusiasts.
  • It is considered one of the most valuable garnet varieties.
  • Its high dispersion gives it a unique sparkle.
  • Demantoid is often used as a centerpiece in fine jewelry.
  • The scarcity of high-quality demantoid specimens contributes to its high market value.

Demantoid Data Sources

Reference URL
Knowledge Graph

Read more


History and Measurement of Density Density, floating, and sinking have been understood since prehistoric times. Aristotle wrote about the difference in density between salt and fresh water. Archime...

Read more

Deep carbon cycle

Deep Carbon Cycle and Carbon Distribution The deep carbon cycle involves the movement of carbon through the Earth's mantle and core. The deep Earth contains a significant amount of carbon, but it ...

Read more