Description
The mineral clinochlor (also called penninite/seraphinite) is a phyllosilicate with the chemical formula (Mg,Fe2+)5Al(Si3Al)O10(OH)8. It is considered the magnesium-containing end member of the chlorite group, a member of the micas. Dark to olive-green, blue-green, or white clinochlor has a vitreous to pearlescent luster and a white streak color. Its cleavage is perfect along the [001] crystal plane, and the crystal system is monoclinic. Its average density is 2.65 and its hardness is 2 to 2.5. Clinochlor is not radioactive. It is named after the Greek words clinos, "slanting," and chloros, "green." The synonym penninite is named after the Apennine Mountains in Italy. Like other chlorite minerals, clinochlor is also found primarily in slightly metamorphic rocks. It is a typical mineral in metamorphosed mafic rocks.
