A class of calcium-poor achondrite meteorite; also known as hypersthene achondrites. They are named after the Greek philosopher Diogenes of Apollonia (fl. fifth century bc), who recognized the cosmic origin of meteorites. Diogenites are composed almost entirely of the mineral bronzite (orthopyroxene), with lesser amounts of the other minerals present in ordinary chondrites. The diogenites probably formed by partial melting of a parent body with a chondritic composition, followed by slow cooling within the crust of that parent body. They are members of the HED (howardite, eucrite, and diogenite) group of meteorites and their parent body is thought to be the asteroid Vesta. See also Basaltic Achondrite.