English

Noun

margarodite ‎(plural margarodites)

1. (mineralogy, obsolete) A hydrous potash mica related to muscovite.
   • 1862, The Quarterly Journal of the Geological Society of London, page 415:

     This optical peculiarity of the Breezy margarodite distinguishes it from the margarodite of the Leinster granite, in which the plane of the optical axes coincides with the long diagonal of the primary rhomb, joining its acute angles.

   • 1904, James Dwight Dana, The System of Mineralogy of James Dwight Dana, 1837-1868:

     Margarodite, as named by Schafhäutl, was the talc-like mica of Mt. Greiner in the Zillerthal (anal. 36); granular to scaly in structure, luster pearly, color grayish white.

   • 1921, Proceedings of the United States National Museum, United States National Museum:

     The alumina of the topaz has gone to form muscovite of the variety known as margarodite with less margarite.

Related terms

• margarite