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Garnet

GarnetJewelryWiki Editorial·4 sources·Reviewed 2026-08-04
Garnet specimen
Garnet specimen. Moha112100, CC BY-SA 3.0 · Wikimedia Commons

A mineral group rather than a single species, which is why its properties are quoted as ranges.

Properties

PropertyValueAuthority
Mohs hardness6½–7½ [1]—
Chemical formulaA3B2(SiO4)3, where A = Fe, Ca, Mn or Mg and B = Al, Fe, Ti or Cr. This is a GROUP formula, not a species one: the letters are positions in a shared structure that different garnet species fill with different elements. That is why grossular, andradite, spessartine, almandine and pyrope are separate minerals rather than colours of one. For a specific stone, see the species — tsavorite is grossular, demantoid is andradite, spessartite is spessartine. [4]—
Crystal systemCubic [3]—
Birthstone monthJanuary [2]—

Sources

  1. International Gem Society — reference charts (Mohs hardness, specific gravity, refractive index) — International Gem Society (IGS reference charts)
  2. Jewelers of America — Birthstones — Jewelers of America (Jewelers of America, Birthstones)
  3. Wikipedia — mineral article infoboxes (crystal system) — Wikipedia contributors (Wikipedia mineral infoboxes)
  4. International Gem Society — gemstone articles — International Gem Society (IGS, gemstone information articles (gemsociety.org))