[exray]

There's a general rule-of-thumb that under 1000/.001 is more likely to be mica. No guarantees, though, because there are plenty of exceptions. One thing you can count on is that line bypass caps like .01, .047, etc will be paper. If its in an RF circuit then the likelihood is that its mica.

Would I replace this one? Maybe not on the first round unless I had reason to suspect it was bad.