Sphene

Orthosilicate

Crystal system: monoclinic (+)

Colour in hand specimen: colourless, yellow, green, brown or black
Cleavage: one, good
Hardness: 5

Colour in plane polarised light: colourless, yellow or typically brown
Pleochroism: moderate if coloured
Relief: high
Birefringence: 0.100-0.192; >4th order
Extinction: inclined
Twinning: simple twins; occasionally lamellar twins

L101 Granite 
L120 Granodiorite

Advanced notes