Ryacolite, pronounced /rāəˈkōlət/, is a relatively uncommon mineral that belongs to the feldspathoid group. It has a complex chemical composition and is found in volcanic rocks, typically as small crystals or as a glassy material. The spelling of the word is influenced by the mineral's Russian origins, where it is spelled "ряколит." In English, the spelling "ryacolite" reflects the Russian pronunciation, with the "y" representing the "ya" sound and the "c" representing the "k" sound.
A mineral of a white or grey colour, with a vitreous lustre, resembling glassy felspar.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.