I know that feeling. I got my first pearl from a skag pile after playing for a few years, and I was so confused to see it just randomly not even from an enemy.

Nice, I recently got the carnage pearl finally! Last night, but it's a sinewy carnage so sort of sucks, man I would love a casual carnage. 

Sorry no screen shots. I just wanted to brag a bit. I have been playing this game for over three years now all characters and all add on's. Today I was farming loot midgets in the Wildlife Exploitation Reserve dropped three pearls and an orange within fifteen minutes. dipity Tungusta,Unending Stalker,Feral Bearcat and A Necromancer legendary class mod. 

Finally got a Pearl!