Two items of interest to PG members in the latest issue of G&G available here: https://www.gia.edu/doc/Winter-2018-Gems-Gemology.pdf

First is on Pinctada maculata pearls (see natural pearl forum) and one on the subject title of this post which can be seen here too: https://www.gia.edu/gems-gemology/wi...ir-host-shells