noun (n)

• a yellow quartz(noun.substance)

  Synonym:
  common topaz, false topaz
  

  source: wordnet30
• a mineral (fluosilicate of aluminum) that occurs in crystals of various colors and is used as a gemstone(noun.substance)

  source: wordnet30
• a light brown the color of topaz(noun.attribute)

  Synonym:
  tan
  

  source: wordnet30
• A mineral occurring in rhombic prisms, generally yellowish and pellucid, also colorless, and of greenesh, bluish, or brownish shades. It sometimes occurs massive and opaque. It is a fluosilicate of alumina, and is used as a gem.(noun)

  source: webster1913