of 90° or near 90°; common in granite and pegmatite rocks Garnet White Commonly occurs 6½-7 as crystals Quartz White Curved conchoidal 7 fracture; brown _smoky_ quartz crystals commonly 6-sided prisms with pyramid-like ends; _chalcedony_, _chert_, and _jasper_ may be a shade brown, too Tourmaline White Dark brown 7-7½ variety is _dravite_; notice hardness, striations on crystals, and triangular cross section of some crystals E. Cannot be scratched by quartz Tourmaline White Dark brown 7-7½ variety is _dravite_; notice hardness, striations on crystals, and triangular cross section of some crystals 10. NONMETALLIC luster, BLACK color