Herbertsmithite

Herbertsmithite is a rhombohedral green-coloured mineral with chemical formula ZnCu3(OH)6Cl2. It is named after the mineralogist Herbert Smith (1872–1953) and was first found in 1972 in Chile. It is polymorphous with kapellasite and closely related to paratacamite. Herbertsmithite has also been found near Anarak, Iran, hence its other name, anarakite. Herbertsmithite is associated with copper mineralization in syenitic porphyries and granites in Chile and in Triassic dolomite formations in Iran. It has also been reported from the Osborn District in the Big Horn Mountains of Maricopa County, Arizona and the Lavrion District Mines of Attica, Greece. Herbertsmithite has a vitreous luster and is fairly transparent with a light-green to blue-green color. Herbertsmithite has a Mohs hardness of between 3 and 3.5. The crystal's density is 3.95 g/cm3. In 2012, the pure synthetic form of herbertsmithite was discovered to be able to exhibit the properties of a quantum spin liquid, due to its Kagome lattice structure.