Hardystonite

hardystonite

vesuvianite

willemite

franklinite

Images

Formula: Ca₂ZnSi₂O₇
Sorosilicate (Si₂O₇ groups), melilite group
Crystal System: Tetragonal
Specific gravity: 3.396 to 3.443 measured, 3.42 calculated
Hardness: 3 to 4
Streak: White
Colour: Light brownish white, pale greyish-white, whitish, very pale pinkish
Solubility:
Common impurities: Al,Fe,Mn,Pb,Mg,Na
Luminescence: Fluorescent dull purple to blue under short wave UV, and blue under long wave (Mindat)
Environments

Metamorphic environments

Localities

At the type locality, the Franklin Mine, Franklin Mining District, Sussex county, New Jersey, USA, hardystonite occurs in a metamorphosed zinc-manganese-iron silicate-oxide orebody (Mindat). Associated minerals include vesuvianite, apatite, franklinite, willemite, rhodonite, calcite and dolomite (HOM).

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