她的订婚戒指镶有一颗璀璨的宝石。

Her engagement ring features a single brilliant ___stone.

这条项链上镶嵌着各种不同颜色的宝石。

The necklace was set with various coloured ___stones.

他正在学习如何鉴定贵重宝石的价值。

He's studying to learn how to value precious ___stones.