jewel 多指贵重的宝石，是经过切削打磨，通常镶嵌在胸针、项链或其它装饰物上的玉。
jewel lery是珠宝的总称，泛指各类珠宝，既指佩带或衣服的珠宝饰物，又指用普通金属、塑料或假宝石制作的装饰物。
stone 特别强调稀少罕见或值钱的矿物。
gem 指经切割、磨光的宝石，引申指珍品、佳作。
参考例句
1. Saphhire is a very hard blue gem. 一种蓝色的非常坚硬的宝石。
2. A very delicate game gem of a Kind. 一款非常精致的宝石对对碰游戏。
3. Game gem : a new game on the Greek mythology, the Jade Temple, built by you. 游戏介绍：新的宝石游戏，希腊神话里的翡翠神殿，由你来建造。
英英解释
n.
1. a crystalline rock that can be cut and polished for jewelry
2. art highly prized for its beauty or perfection
3. a person who is a brilliant and precious as a piece of jewelry
4. a sweet quick bread baked in a cup-shaped pan
5. a precious or semiprecious stone incorporated into a piece of jewelry
