Actual Gem

someone who embodies the qualities that most people do not have. a very nice person with a kind heart and a warm soul.

an actual gem differs from a gem:
actual gems are people that are not described by metaphor (he's a nice guy) but compared to by actuality and factual observation. (they are an actual gem to be treasured)

Jason Butler is an actual gem. He is one of the nicest guys I have ever met