The Oxford Thesaurus An A-Z Dictionary of Synonyms - jewel n.

1) gem, gemstone, brilliant, ornament, bijou, Colloq rock, sparkler: Thieves stole a diamond necklace and an heirloom brooch set with precious jewels. 2) treasure, marvel, find, godsend, gem, pearl, prize, boon, Colloq catch: What would you do without your secretary - she's an absolute jewel!