The museum's security was breached, and the famous diamond jewel was stolen.

jewel 是名词，意思是"珠宝、宝石"，特指珍贵且经过切割打磨的宝石或贵重金属制成的装饰品。这个词来自古法语 joel，与 joy（喜悦）同源，因为珠宝能给人带来愉悦感。