Garnet: more than one mineral hiding under one name

Garnet is actually a group of several closely related minerals (almandine, pyrope, spessartine, grossular, andradite, and uvarovite among others) that share a similar crystal structure but vary in exact composition and color, which is why garnet comes in nearly every color except true blue. Hardness runs roughly 6.5 to 7.5 depending on the exact species, dense enough to concentrate in stream gravels the same way quartz does. Garnet commonly forms in metamorphic rock, especially schist, and often shows a distinctive rounded, many sided crystal habit (a rhombic dodecahedron is the classic garnet crystal shape) that makes loose crystals recognizable even before cutting.