Wordnet 3.0
NOUN (1)
1. 
 a crystalline rock that can be cut and polished for jewelry; 
- Example: "he had the gem set in a ring for his wife"- Example: "she had jewels made of all the rarest stones"[syn: gem, gemstone, stone]
WordNet (r) 3.0 (2006):
gemstone
    n 1: a crystalline rock that can be cut and polished for
         jewelry; "he had the gem set in a ring for his wife"; "she
         had jewels made of all the rarest stones" [syn: gem,
         gemstone, stone]