Grossular (Ca₃Al₂(SiO₄)₃) is the calcium-aluminum end-member of the garnet group and one of the most variably colored garnet species. Its name comes from Latin “grossularia” (gooseberry) for its original pale-green specimens. Famous gem varieties include tsavorite (vivid chrome-vanadium green from Tanzania/Kenya) and hessonite (cinnamon-orange iron-bearing from Sri Lanka and Italy). Grossular is a classic skarn species, formed at the contact between calcareous rocks and granitic intrusions.
Key Facts
- Mohs hardness 6.5–7.
- Isometric; classic dodecahedral and trapezohedral crystals.
- Color extremely variable: green (tsavorite), orange (hessonite), pink, yellow, white, colorless.
- Forms a continuous solid-solution series with andradite (Ca-Fe garnet).
- “Grossular massive” green variety from Quebec is sometimes used as jade substitute.
Notable Localities
Lelatema Mts (Tanzania) and Tsavo (Kenya) yield gem tsavorite. Asbestos and Jeffrey Mine (Quebec) produce massive green Grossular. Sri Lanka and Italy supply orange hessonite.
Found at these Localities
- Merelani Hills (梅雷拉尼山(坦桑石产地))
- Italian Volcanic Province (Vesuvius / Lipari / Etna) (意大利火山矿物产地)
