a variously coloured amorphous mineral consisting of hydrated aluminium silicate and occurring in cracks in some sedimentary rocks
Word origin
C19: from Greek allophanēs appearing differently, from allo- + phainesthai to appear
allophane in American English
(ˈæloʊˌfeɪn; ˈæləˌfeɪn)
noun
a soft clay mineral, a translucent, hydrous silicate of aluminum, of varying composition and color, typically occurring as incrustations in chalk and sandstone
Word origin
allo- + -phane, as in Gr allophanēs, appearing otherwise: so named because it changes appearance under the blowpipe