CHEMISTRY - (Mg,Fe)7SiO22(OH)2
alternatively (Mg,Fe)2(Mg,Fe)5SiO22(OH)2
CRYSTALLOGRAPHY - Orthorhombic
CRYSTAL GROWTH AND HABITS - Crystals commonly form bladed or prismatic aggregates. It is also fibrous or can be found in asbestiform masses.
COLOR AND OPTICAL PROPERTIES - Anthopyllite is commonly gray to brownish in color (clove brown), to yellowish or brownish green. It is transparent to translucent.
HARDNESS - 5.5 - 6
SPECIFIC GRAVITY - 2.9 - 3.5
LUSTER - Vitreous to slightly pearly along cleavage faces
STREAK - White
BREAKABILITY - Anthophyllite has a very good cleavage developed along {210} producing angles of 54.5o and 125.5o. It also has good cleavage along {010} and {100}. It is brittle and fibers are elastic.
OCCURRENCE - Anthophyllite is a fairly rare mineral that occurs in medium to high grade metamorphic rocks derived from argillaceous sediments. It can also occur through the metamorphism of rocks rich in Olivine.
ASSOCIATED MINERALS - Talc, Chlorite, Cordierite, Sillimanite, Mica, Olivine, Garnet, Staurolite, Plagioclase feldspars
MINERAL NAME - From the Latin anthophyllum, meaning clove, due to the brownish color of the mineral.