Just sharing a basic resource I stumbled upon while doing some research. The site seems to have a good general coverage of pearl information which is well organized, although lacking the depth in this forum, but still better than wikipedia. It's a distributor's site so I can't be 100% sure the information isn't biased and I know nothing of their quality of goods.
http://www.pearldistributors.com/pea...edia-index.php