Grossular
Grossular is a silicate mineral prized by collectors for its exceptional color range, with known Chinese sources.
About Grossular
Grossular is a silicate mineral in the garnet group (ugrandite series) and has the chemical formula Ca3Al2(SiO4)3. It crystallizes in the isometric system and is one of the most visually varied minerals in the collector market. Its combination of structural character and global distribution make it a recognized species in both systematic and aesthetic collections.
Identification & care
Crystals commonly develop as dodecahedral, trapezohedron; combinations; granular. Its color range is broad, including colorless, white, pale green, rich green (tsavorite), orange (hessonite/cinnamon stone), yellow, pink (leuco-grossular), and brown. The luster is vitreous, resinous, the streak is white, and specimens range from transparent to translucent. The fracture is conchoidal, uneven, which is one of its key identifying features.
Collector context
How it forms
In terms of geology, Grossular forms in metamorphic skarns (contact metamorphism with calcareous rocks), serpentinites, crystalline limestone; alluvial gem gravels. It is commonly found in association with diopside, wollastonite, calcite, vesuvianite, tremolite, zoisite (for tsavorite).
Classic Chinese localities
Grossular is widely represented across Chinese provinces, including Fujian, Gansu, Anhui, Guangdong.
Why collectors care
Grossular is a frequently-sought species in serious collections because its habit is recognizable, its color often strong, and its best examples unmistakable even at a distance. Chinese material has driven much of the recent visual shift in the species — sharper crystals, deeper colors, cleaner matrix.
What affects value
Value in Grossular is assessed, in typical order of weight, against: (1) locality provenance; (2) size relative to the species norm; (3) crystal form and termination sharpness; (4) color saturation and zoning; (5) transparency and internal clarity; (6) matrix quality and aesthetic balance; (7) condition (absence of damage, chips, or repair). Cleaning quality and verified locality documentation act as multipliers across the above.
Naming history
The name Grossular has a specific etymological and historical context — see Mindat's reference entry for provenance details. We have retained naming data at the record level; published prose is paraphrased from factual fields rather than copied from source.