Crystal Structure
Ca₃Al₂(SiO₄)₃.
Elemental Composition (by mass)
| Element | Mass % | Visual |
|---|---|---|
| O Oxygen | 42.62% | |
| Ca Calcium | 26.69% | |
| Si Silicon | 18.71% | |
| Al Aluminum | 11.98% |
Computed from simplified end-member formula. Solid-solution series, water content, and trace substitutions cause real-world variation.
IMA Abbreviation (Whitney-Evans 2010)
Grs
→ Grossular
Garnet
Standard symbol from American Mineralogist (Whitney & Evans, 2010). Used in thin-section labeling, phase diagrams, and IMA-style species records.
Pronunciation
/ˈɡrɒsjələr/
↔ GROSS-yuh-lar
from gooseberry (Latin grossularia)
Luster
vitreous
Standard vitreous.
Diaphaneity (Transparency)
transparent-to-translucent
Including tsavorite (gem) and hessonite (transparent).
Type Locality
Wilui River, Sakha — Russia
Described 1808 by Werner
› Browse all type localities
Magnetism
Category:
diamagnetic
Test result:
Very slightly repelled or null
Ca-Al garnet — no transition metal; pure grossular is diamagnetic.
Test with rare-earth magnet (N42 or N52 neodymium). Suspend specimen on thread for sensitive paramagnetic detection. Diamagnetic minerals are weakly repelled (visible only with strong magnets like bismuth).
Specific Gravity
3.42–3.72
g/cm³
medium
Ca-Al garnet; includes tsavorite, hessonite.
For comparison: water = 1.00, glass ≈ 2.5, quartz = 2.65, corundum ≈ 4.00, galena ≈ 7.50, gold ≈ 19.3.
Geological Setting
Forms in contact-metamorphic calc-silicate rocks.
Mohs 6.5–7
Vickers (~) 1400 HV
Knoop (~) 1100 HK
Geological setting
Skarn
Element composition by mass
Formula: Ca₃Al₂(SiO₄)₃ · molar mass: 450.44 g/mol
| O | 42.62% | |
| Ca | 26.69% | |
| Si | 18.71% | |
| Al | 11.98% |
Computed from atomic weights (IUPAC 2021). Site-occupancy groups (Fe,Mn) split equally.
GroupGarnet Group
Mohs Hardness
6.5–7
Grossular sits at 6.5–7 on the Mohs scale — harder than glass; scratches steel.
Colors:
Streak
White
White
Crystal system
Isometric (Cubic)
Isometric (Cubic)
SilicatesSilicates (Nesosilicates)
TL;DR · 1 min read
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.
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.
More minerals to explore
Spessartine (锰铝榴石)
Isometric (Cubic)
Forsterite (镁橄榄石)
Orthorhombic
Andalusite (红柱石)
Orthorhombic
Titanite (Sphene) (榍石)
Monoclinic
Uvarovite (钙铬榴石)
Isometric (Cubic)
Kyanite (蓝晶石)
Triclinic
Other Members of the Garnet Group
石榴石族
- Almandine (铁铝榴石)
- Andradite (钙铁榴石)
- Pyrope (镁铝榴石)
- Spessartine (锰铝榴石)
- Uvarovite (钙铬榴石)