fahlunite Min.
(ˈfɑːlənaɪt)
[f. (by Hisinger, 1808) Fahlun, in Sweden + -ite.]
A hydrous silicate of aluminium and iron, resulting from the alteration of iolite.
| 1814 T. Allan Min. Nomen. 18 Fahlunite Kars. 112 b. 1879 Rutley Stud. Rocks xiv. 298 The rock contains as accessories..hydrargillite, fahlunite, gahnite, etc. |