Spinel
WordNet

noun


(1)   A hard glassy mineral consisting of an oxide of magnesium and aluminum; occurs in various colors that are used as gemstones
WiktionaryText

Noun



  1. any of several hard minerals of cubic symmetry that are mixed oxides of magnesium and aluminium and are used as gemstones of various colours
  2. any crystalline material, not necessarily an oxide, that possesses the same crystal structure as this mineral
 
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