botryogen
/ˈbɒtrɪədʒ(ə)n/Mineralogy
noun
A magnesium-containing mineral that is an alteration product of pyrite typically occurring as reddish crystalline masses, often botryoidal or reniform.
- Botryogen is a basic hydrated sulphate of magnesium and ferric iron, MgFe3+(SO4)2(OH)·7H2O. Crystal system: monoclinic..
Origin
Mid 19th century; earliest use found in James Dana (1813–1895), geologist, zoologist, and teacher. From German Botryogen from ancient Greek βοτρυο-, combining form (in e.g. βοτρυόδωρος grape-producing) of βότρυς bunch of grapes + γενής, so called in allusion to the botryoidal habit of the mineral. For the formation compare alunogen.