muscovite

Etymology

In 1850 from Muscovy glass + -ite, from the province Muscovy in Russia. Named by James Dwight Dana.

noun

1. (mineralogy) A pale brown mineral of the mica group, being a basic potassium aluminosilicate with the chemical formula KAl₂(Si₃Al)O₁₀(OH,F)₂; used as an electrical insulator etc.
   Do you enjoy the amber glow seen through the isinglass window of a wood stove? […] Muscovite (colorless, white, or pale red or green) mica is also common[…]; it was named for Moskva (Moscow), where much of Europe's mica was mined. Isinglass, mentioned above, consists of thin, transparent sheets of muscovite. 2009, James S. Monroe, Reed Wicander, The Changing Earth: Exploring Geology and Evolution, 5th edition, Belmont, Calif.: Brooks/Cole, page 76