Palagonite-tuff, usually associated with basalt-lavas, is fine-grained, red, brown, and sometimes greenish or yellowish in colour. Under the microscope it is seen to be composed of minute fragments of volcanic glass, crowded amongst which are granules and crystals of augite, olivine, plagioclase, and magnetite. It occurs in Sicily, the Canary Islands, the Faroe Islands, Iceland, and Scotland. See IGNEOUS ROCKS.
Palagonite-tuff
Chambers's Encyclopaedia, Volume 7: Maltebrun to Pearson, p. 709
Source scan(s): p. 0722