A hard, fine-grained rock, rich in albite, resulting from contact metamorphism of shales, slates, etc.
Originally described by Beudant as a mineral species, a form of albite..
Origin
Mid 19th century; earliest use found in Charles Shepard (1804–1886). From French adinole from ancient Greek ἁδινός crowded, abundant + an element of uncertain origin (perhaps French -ole, although the semantic motivation is unclear).