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.
(..) Well, if they'd send us more guys, maybe... ...and bomb the hell out of the North, they might give up. I wanted to see eXotic Vietnam, the jewel of Southeast Asia. I wanted to meet interesting and stimulating people of an ancient culture... ...and kill them. I wanted to be the first kid on my block (..)1987 Full Metal Jacket