I, too, would be curious to hear this. The more I look at the pic I think a hybrid could be a likely option. I can not say I have seen very many pics of full pearls with irregular shaped spotting. With this being said, I have also read that pearls vary a ton.
The color and the looks of the spots is what makes me say pearl, looks alot like one of my pearls. The pattern is a bit off, seems a little less organized than normal. Could just be an odd pattern or maybe its a pearl hybrid.