Garnet group

Formula:  (Ca,Fe,Mg,Mn)3(Al,Cr,Fe,Mn,Si.Ti.V,Zr)2(SiO4)3-x(OH)4x

Origin of name:  From Latin granatus = like a grain

 

Crystal system:  Cubic

Crystal class:  4/m -3 2/m

Twinning:

Unit cell:

 

Colour:  Dark yellow, dark reddish-brown

Diaphaneity:  Semitransparent

Luster:  Vitreous, resinous, adamantine

Habit:  Crystals usually dodecahedrons or trapezohedrons; massive; granular

Hardness:  6 to 7.5

Specific gravity:  3.4 to 4.3

Cleavage:  {110} parting sometimes developed

Tenacity:

Streak:

 

Synonyms/varieties:

 

Comments:  Members of the garnet group: almandine, andradite, calderite, goldmanite, grossular, henritermierite, hibschite, katoite, kimzeyite, knorringite, majorite, morimotoite, pyrope, schorlomite, spessartine, uvarovite

 

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