Garnets

Garnets: silicates composed of a divalent metal (Magnesium, Iron, Manganese, or Calcium) and a trivalent metal (Iron, Aluminum, or Chromium), crystallizing in the Isometric System in dodecahedral or rhombic dodecahedral forms, often combined. Garnets can also occur in massive form; their Mohs hardness ranges from 6.5 to 7.5. Among the pure compounds, there is solid solution, which is complete only in some cases (such as Pyrope-Almandine, Almandine-Spessartine, and Grossular–Andradite).

back to the gemological glossary