[eviljeff]

unless you have a strong read, this is an instamuck after he raises you on the turn. honestly I'd check this turn. he's not folding a diamond, and a check on the turn encourages a bluff from him on the river.

edit: hmmm, actually I didn't do the math right. 9.25:1 is probably good enough to catch our four-outer as we'll get extra action from a high flush. also you have outs to a split pot. still, I prefer a check on the turn. the river is a definite fold.