In our listings we use the HMS-ISGS grading system. A plus (+) sign after a grading means that it is in between that grade and the above grade. A plus-plus (++) after a grading means that it could possibly be included in the above grade. Other abbreviations used: w/o – with operculum; w/p – with periostracum
There is however an exception. We only use the GEM grade for Cypraeidae, Marginellidae, Olividae and Ovulidae. For all other families we use F++, which means that the really GEM shells are also included in this denomination.
All shells are live taken, unless otherwise specified.