Last January 12, I found some Exogyra sp. oysters in a limestone Late Campanian / Early Maastrichtian strata (SE Pyrenees, Catalonia, Spain), who turned to show abundant beekite rings. I owe to @abyssunder my knowledge of this mineral phenomenon, which, in my area,occurs mainly over laminar-type shells like oysters' (It can occur on other fossils, though).               Have you fossils with beekite rings ?