Brucite is a hydroxide mineral with the composition of Mg(OH)2. Also, brucite has been used as a group name for M2+(OH)2 where M = Fe, Mg, Mn, Ni. Brucite is comprised of a plane of Mg cations, with each Mg octahedrally coordinated by edge-sharing OH groups, thus forming an infinite two-dimensional sheet. Brucite primarily occurs as a contact metmorphic mineral in dolomites and Mg-rich limestones from the alteration of periclase, and in serpentinites and chlorite schists.