bbnnyy168, unless you're investing in, say...hamadamas, Cortez, or Basra pearls, I don't feel authentication is necessary. Thanks to China, pearls have become more commonplace. For Philippine pearls, I would only consider authentication for Jewelmer golden south sea pearls--and if I did buy them from Jewelmer, I'm sure they'd come with the right papers.
Topetang, I'm not sure P-G's expertise would apply to coconut pearls, considering that our interest is limited to pearls from oysters, mussels and other shellfish.