Lil Uzi Vert is officially the biggest Marilyn Manson fan ... unless you know of any others who spent six figures to make an iced out pendant in his likeness.

Uzi was rocking his newest piece at Coachella this weekend. The image of Manson rockin' Mickey Mouse ears is damn near priceless -- the chain and pendant together are made up of 16,000 diamonds totaling 155 carats.

Celeb jeweler Ben Baller delivered the goods to Uzi on Sunday, and IF & Co. Jewelers made it for $220k. We're told the labor alone cost $50,000.

Manson is the only person Uzi follows on IG, so his love for the rocker is deep ... and expensive.