keratophyren.

1889 Geol. Mag. Feb. 71 Microscopical examination and chemical analysis show that these rocks consist, in part at least, of soda-felsites or keratophyres. The keratophyres (so named from their resemblance to hornstone) were first described by Gümbel.

1900 H. E. Gregory Geol. Aroostook Volcanic Area 163 The group of soda trachytes or keratophyres.

1937 A. Johannsen Descr. Petrogr. Igneous Rocks III. 49 The keratophyres are similar in appearance [to normal trachytes] but usually are much weathered and show brown or green tones.

1956 E. W. Heinrich Microsc. Petrogr. iii. 51 Trachytes occur as volcanic rocks and minor hypabyssal intrusives... Albitized types (keratophyres) occur with spillites.

1972 Gloss. Geol. (Amer. Geol. Inst.) 385/2 Keratophyre, a name originally applied by Gümbel..to trachytic rocks containing highly sodic feldspars, but now more generally applied to all salic extrusive and hypabyssal rocks characterized by the presence of albite or albite-oligoclase and chlorite, epidote, and calcite, generally of secondary origin. Originally the term was restricted to lavas of pre-Tertiary age but this distinction is not recognized in current usage.