The proper word to use when referring to various creatures’ (e.g. echinoids and forams) shells or skeletons. Related Articles: Fifteenth century magico-medicinal mineralsSalthill Quarry, Clitheroe: A resource degradedJade: Imperial green gem of the East (Part 5) - the world marketplaceColonising skeletal substrates: Encrusters and borers from the Upper Jurassic oyster shell beds of Central PolandBook review: Breakthroughs in Geology: Ideas that transformed Earth Science, by Graham Park« Back to Glossary Index