Feldspar · Orthoclase Feldspar

Grey-Black Orthoclase

Grey to black orthoclase is a little-used ornamental feldspar recognisable by its white perthitic streaking. It is far more common in the field than in jewellery.

Colour
grey

Transparency
Variable (translucent to opaque)

RI
1.518–1.526

SG
2.55–2.61

Mohs
6.0–6.5

Birthstone
June

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