Garnet

Orthosilicate

Crystal system: cubic

Colour in hand specimen: typically red
Cleavage: none
Hardness: 6-7.5

Colour in plane polarised light: colourless, pale pink 
Pleochroism: none
Relief: high
Isotropic

M130 Garnet schist
Portsoy, Banffshire
Euhedral porphyroblasts of dark-red garnet, with quartz, mica and other minerals in a medium-grade metamorphic rock.

L504 Garnet schist

The garnet group encompasses a wide range of compositions, and consequently a range of optical and physical properties. The properties detailed above are typical of pyrope (Mg₃Al₂Si₃O₁₂), almandine (Fe²⁺₃Al₂Si₃O₁₂) and grossular (Ca₃Al₂Si₃O₁₂).