Definition of allagite in English:

allagite

noun

Mineralogy
rare
  • A green or brownish-red mineral of uncertain identity (perhaps an altered form of rhodonite) consisting of a silicate and carbonate of manganese.

Origin

Early 19th century. From German Allagit from ancient Greek ἀλλαγή change, alteration (from ἄλλος other; the guttural suffix is unexplained) + German -it, with alteration of the ending after words in -ite; the mineral was apparently so called on account of its change of appearance on exposure.

Pronunciation

allagite

/ˈaləɡʌɪt/