means A precious stone, or a piece of fine jewelry made with one, often cut and polished to dazzle — and figuratively, anything or anyone treasured as rare and valuable.

from From Old French 'joel' or 'jouel,' a precious ornament, which came into English after the Norman Conquest. Its deeper root is debated: many trace it to Latin 'jocus,' meaning a joke or plaything (the same source as 'jewel's' cousin 'joy'), as if a gem were a delightful trifle — though some scholars instead link it to Latin 'gemma,' a bud or gem. Either way, the word arrived in English wrapped in the glitter of medieval courts.