An Unusual Pearl: Coated or Not?
Roskin Gem News ReportGary Roskin
Conch Pearl: Coated, or not?
Identification of pearl coatings can be a bit tricky, especially if the coating has been performed...
Ti Surface Diffusion: Just when you thought it was an easy identification
New research shows that the titanium surface diffusion treatment is being polished off the facets, but left inside cavities and fractures. Stone Group...