On the same website you can find these:
http://www.davidandcompany.com/product_detail.php?product_id=2185410&Metal=18kt%20YG&Stone=&Style=New&Type=Necklace/Pendant
13 X 18mm Baroque South Sea Pearl Necklace
I purchesed from them and received exactly what was shown in the photo and the same size.
It goes without saying that the more you pay them, the better the quality you receive. Overall, I have had no problems or complains dealing with them.
Burmese pearls were once considered the absolute best big pearls before the junta ruined the industry. Maybe these are those. Let's hope that along with democratization, the Myanmar pearl industry revives.