Almandine | |
Chemical Formula |
Fe2+3Al2Si3O12 |
Species |
Silicates |
Crystal System |
Isometric |
Mohs Scale |
7 |
Specific Gravity |
4.05 |
Color |
reddish orange to red, slightly purplish red to reddish purple and usually dark in tone |
Streak |
White |
Luster |
Vitreous, Resinous |
Refractive Index |
n = 1.83 |
Diaphaneity |
Transparent, Translucent |
Cleavage |
none |
Fracture |
Sub-Conchoidal |
Crystal Habit:Typically well-formed dodecahedra or trapezohedra, to 1 m; also in rounded grains and massive. | |
Geological Setting:The most common garnet, typically in mica schists and gneisses, from regionally metamorphosed argillaceous sediments and pelites; also in contact metamorphic hornfels. In granites and eclogites; in sedimentary rocks; as a detrital mineral. |