He owns several successful businesses but this company is the 'jewel in the crown'. [=this company is the most valuable/important/admired]
The guests were heavily 'jeweled'. [=the guests were wearing a lot of jewelry]
The building is regarded as one of the 'jewels' of modern architecture.
(..) famous and powerful. Everything Horace values. Professor Slughorn's gonna try to collect you, Harry. You would be his crowning jewel. That's why he's returning to Hogwarts. And it's crucial he should return. I fear I may have stolen (..)2009 Harry Potter and the Half-Blood Prince