The 6th edition of Renee Newman's excellent Pearl Buying Guide is now available!
IMO this is one book every pearl buyer should read. I just placed my order. (I have the 5th edition, but that dates from 2010 and a lot has happened since then, especially with freshwater pearls.)
Here it is on Amazon at $15.66:
(I see lower priced used copies but I would think those would likely be earlier editions.)
For more information, see: http://reneenewman.com/pearl.htm
Changes in the NEW 6th Edition:* 186 new photographs of pearls, pearl jewelry, neck pieces and pearl x-radiographs* Updated information on pearl types, geographic sources and freshwater pearls* Expanded chapter on "Creating Unique Pearl Jewelry with Colored Gems."
* Expanded chapter on natural pearls
* New pearls and pearl jewelry styles