hydrous mica
mineral group of any of the illite group of clay minerals, including illite, bramallite (a sodium illite), and glauconite.
en-US/ˈhaɪdɹəs ˈmaɪkə/
en-GB/ˈhaɪdɹəs ˈmaɪkə/
mineral group of any of the illite group of clay minerals, including illite, bramallite (a sodium illite), and glauconite.