The other day I was reading a French comic when I noticed one of the characters said this:
Vous mentez! C'est du piment rouge!
Note the use of the partitive. This strikes me as a little odd, since I would think red peppers would be countable (like bananas, for instance). Shouldn't it be
C'est un piment rouge!
instead? I'm not a native French speaker, so I'm not entirely certain.