Lesser known members include phlogopite, paragonite, glauconite, and zinnwaldite, and the three major divisions are the interlayer-deficient type, so named because of the lack of calcium ions within the TOT (tee-oh-tee) layer, the brittle type, and the true type.
Although the layers of this group of minerals appear to have hexagonal symmetry, they are in actuality monoclinic or triclinic. Lesser known members include phlogopite, paragonite, glauconite, and zinnwaldite, and the three major divisions are the interlayer-deficient type, so named because of the lack of calcium ions within the TOT (tee-oh-tee) layer, the brittle type, and the true type. Encompassing the phyllosilicate class of minerals, they are ubiquitous in sedimentary, metamorphic, and igneous rock. FTP, name this brittle, flaky mineral whose most well known times are muscovite and biotite.
Although the layers of this group of minerals appear to have hexagonal symmetry, they are in actuality monoclinic or triclinic.
mica