LIZARDITE VAR ANTIGORITE, TULLAH TASMANIA

Lizardite is a mineral belonging to the serpentine subgroup, characterized by the chemical formula Mg3(Si2O5)(OH)4, and is the most prevalent mineral within this category. It is also classified under the kaolinite-serpentine group. Lizardite can form a solid-solution series with the nickel-rich mineral népouite, which has the formula Ni3(Si2O5)(OH)4 as its pure end-member. Intermediate compositions, represented as (Mg,Ni)3(Si2O5)(OH)4, can occur, featuring varying amounts of magnesium and nickel. However, lizardite is significantly more common than the rarer népouite, which typically arises from the alteration of ultramafic rocks. The extremely fine-grained, scaly variety of lizardite, sometimes referred to as orthoantigorite, constitutes a large portion of the serpentine found in "serpentine marbles." This mineral exhibits a triclinic crystal system, possesses perfect cleavage in one direction, and can appear in shades of white, yellow, or green. Lizardite may be translucent or opaque and has a distinctive soapy texture. In some cases, it can form pseudomorphs after minerals like enstatite, olivine, or pyroxene, leading to the designation of bastite, which may display a silky luster.