Definition of allophane in English:

allophane

noun

Mineralogy
  • An amorphous clay mineral, typically pale blue, consisting essentially of hydrated aluminium silicate.

Origin

Early 19th century; earliest use found in Annals of Philosophy. From allo- + -phane, after German Allophan, itself apparently after Byzantine Greek ἀλλοϕανής, the mineral being so named on account of its unusual appearance.

Pronunciation

allophane

/ˈaləfeɪn/