#quartz  a hard glossy mineral consisting of silicon dioxide in crystal form; present in most rocks (especially sandstone and granite); yellow sand is quartz with iron oxide impurities
  supertype:  mineral  solid homogeneous inorganic substances occurring in nature having a definite chemical composition
  substance:  silicon  silica
  subtype:  rock_crystal__transparent_quartz__transparentquartz  a clear quartz used in making electronic and optical equipment
     subtype:  rhinestone  an imitation diamond made from rock crystal or glass or paste
  subtype:  cairngorm__smoky_quartz__smokyquartz  a smoky yellow or brown quartz
  subtype:  amethyst  a transparent purple variety of quartz; used as a gemstone
  subtype:  chalcedony__calcedony  a milky or grayish translucent to transparent quartz
     subtype:  agate  an impure form of quartz consisting of banded chalcedony; used as a gemstone and for making mortars and pestles
        subtype:  moss_agate  an agate with brown, black, or green moss-like markings
     subtype:  bloodstone__heliotrope  green chalcedony with red spots that resemble blood
     subtype:  carnelian__cornelian  a translucent red or orange variety of chalcedony
     subtype:  chrysoprase  a green variety of chalcedony valued as a gemstone
     subtype:  onyx  a chalcedony with alternating black and white bands; used in making cameos
        subtype:  sardonyx  an onyx characterized by parallel layers of sard and a different colored mineral
     subtype:  plasma.chalcedony  a green slightly translucent variety of chalcedony used as a gemstone
     subtype:  sard__sardine__sardiu  a deep orange-red variety of chalcedony
  subtype:  citrine  semiprecious yellow quartz resembling topaz
  subtype:  rose_quartz  a translucent rose-red variety of quartz used for ornaments
  subtype:  sunstone__aventurine  a translucent quartz spangled with bits of mica or other minerals
     subtype:  goldstone  aventurine spangled densely with fine gold-colored particles
  subtype:  common_topaz__topaz__false_topaz__falsetopaz  a yellow quartz

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