Sentence:  Although there are dozens of different types of gems, among the best known and most important are diamond, ruby and sapphire, emerald and other gem forms of the mineral beryl, chrysoberyl, tanzanite, tsavorite, topaz and <WSD>jade</WSD>. 
Meaning of the word marked with <WSD> tags:  (gem) A semiprecious stone, either nephrite or jadeite, generally green or white in color, often used for carving figurines.