Mineral Information and Data:

Grossular
Ca₃Al₂(SiO₄)₃ [CNMNC approved formula]

Named in 1811 for the green color of gooseberries (Ribes grossularium) because the original specimens were this color.

IMA status :	Approved Species 1960 ()
CLASSIFICATION
Dana (8^th edition) :	51.04.03b.02
	(51) Nesosilicate Insular SiO4 Groups Only
	(51.04) with cations in [6] and >[6] coordination
	(51.04.03b) Garnet group (Ugrandite series)

Nickel-Strunz (10^th edition) :	09.AD.25
	(09) Silicates
	(09.A) Nesosilicates (Isolated tetrahedron) structures
	(09.AD) Nesosilicates without additional anions; cations in [6] and/or greater coordination

Crystal system:	Cubic System
Point group (H-M):	m3m (or 4/m 3 2/m) — hexoctahedral
Unit cell:	a = 11.85 Ǻ
Crystal Habit:	Crystals dodecahedrons or trapezohedrons; massive, compact; granular; embedded grains

Color:	Colorless, white, gray, yellow to green, brown, pink, red, black
Diaphaneity:	Transparent to opaque
Luster:	Vitreous to resinous
Hardness (Mohs):	6.5 to 7
Measured Density:	3.4 to 3.6 g/cm³
Cleavage:	Parting on {110} rarely observed
Tenacity:	Brittle
Fracture:	Uneven to conchoidal
Streak:	White

Geologic Setting:	In contact and regionally metamorphosed calcareous rocks, or rocks which have undergone calcium metasomatism; in some schists and serpentinites.
Mineral Association:	Calcite, dolomite, epidote, clinozoisite, wollastonite, scapolite, vesuvianite, diopside, tremolite, quartz

Synonyms/varieties:	Grossularite, hessonite/essonite (orange to red var.), tsavorite/tsavolite (gree, Cr/V-rich var.)
Other Properties:	Gemstone Rare.
Comments:	Forms three series: with andradite; with hibschite and katoite; and with uvarovite