jewel
noun
1 a crown encrusted with priceless jewels:
gem, gemstone, precious stone, semiprecious stone, stone, brilliant;
baguette, cabochon;
informal sparkler, rock;
archaic bijou.
3 the jewel of his collection | a jewel of a poem:
finest example/specimen, choicest example/specimen, best example/specimen, showpiece, pearl, flower, pride, pride and joy, cream, crème de la crème, jewel in the crown, nonpareil, glory, wonder, prize, boast, pick;
masterpiece, chef d'oeuvre, pièce de résistance;
outstanding example, shining example;
Latin ne plus ultra;
informal the pick of the bunch.