Forum:How rare are "pearls" exactly?

Hello everyone, as the topic suggests, i was wondering how rare the new pearlescent items truly are. I've killed Crawmerax on playthrough 2 25 times now and have yet to see one drop. I understand they can be the best weapons in game atm, but 25 kills and nothing? I'm curious if i'm missing something here. For instance, do they only drop when in a party playing Co-Op as the one of the "loading screen hints" might be suggesting; "more people = stronger enemies / stronger enemies = better loot" (or something along those lines). Or does RNG hate my soul that much. Just wondering is all. If anyone wants to add me on Xbox Live send me a friend request. Thanks in advance. TheHomieRome