| Crystal System |
Isometric |
| Chemical Comp.. |
(Mg,Fe2+)(Al,Cr)2O4 |
| Color |
Brown
to Opaque |
| Pleochroism |
None |
| Cleavage |
Poor |
| Relief |
Very
High |
| Birefringence |
None - Isotropic |
| 2V | -- |
| Optic Sign |
-- |
| Twinning |
Single, Simple |
As Cr content increases, spinel becomes more opaque in thin section. Ol = Olivine; Sp = Spinel; Opx = Orthopyroxene; Cpx = Clinopyroxene.
