1837, of crystals, from inter- "between" + facial (adj.).
Entries linking to interfacial
inter-
word-forming element used freely in English, "between, among, during," from Latin inter (prep., adv.) "among, between, betwixt, in the midst of" (also used extensively as a prefix), from PIE *enter "between, among" (source also of Sanskrit antar, Old Persian antar "among, between," Greek entera (plural) "intestines," Old Irish eter, Old Welsh ithr "among, between," Gothic undar, Old English under "under"), a comparative of root *en "in."
A living prefix in English from 15c. and used with Germanic as well as Latinate words. Spelled entre- in French; most words borrowed into English in that form were re-spelled 16c. to conform with Latin except entertain, enterprise. In Latin, spelling shifted to intel- before -l-, hence intelligence, etc.
facial adj.
c. 1600, "face to face," from French facial, from Medieval Latin facialis "of the face," from facies (see face (n.)). Meaning "pertaining to the face" in English is from 1786. The noun meaning "beauty treatment for the face" is from 1914, American English. Middle English had faciale (n.) "face-cloth for a corpse" (early 14c.).