1. 宝石
    A jewel is a precious stone used to decorate valuable things that you wear, such as rings or necklaces.

    e.g. ...a golden box containing precious jewels.
           盛放贵重宝石的金盒子

2. 珍宝；珍贵的东西；出色的人；美貌超群的人
    If you describe something or someone as a jewel, you mean that they are better, more beautiful, or more special than other similar things or than other people.

    e.g. Walk down Castle Street and admire our little jewel of a cathedral...
           沿城堡街走下去，欣赏一下我们美妙绝伦的大教堂。
    e.g. Alan, you're a jewel.
           艾伦，你真是出类拔萃呀。

3. 王冠上的宝石；最有成就（或最值得骄傲）之处
    If you refer to an achievement or thing as the jewel in someone's crown, you mean that it is considered to be their greatest achievement or the thing they can be most proud of.

    e.g. His achievement is astonishing and this book is the jewel in his crown.
           他的成就令人震惊，而这部书则是他的杰作。