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CategoryCopper minerals

Zinc minerals

Halide minerals
Chemical formulaZnCu3(OH)6Cl2
ColorLight green, blue-green
Crystal systemTrigonal
CleavageDistinct to good
Mohs Scale hardness3-3½
StreakLight green

Herbertsmithite is a mineral with chemical structure ZnCu3(OH)6Cl2. It is named after the mineralogist Herbert Smith and was first found in 1972 in Chile. The mineral has properties considered, generically, to be of potential use in quantum computing. A polymorph of kapellasite and closely related to paratacamite, is generally found in and around Anarak, Iran, hence its other name, Anarakite. Herbertsmithite is associated with copper mineralizations in syenitic porphyries and granites.

Recent studies at MIT have investigated purified herbertsmithite in a study to determine if it is a new state of matter known as a string-net liquid (see also: string-net). Current research is incomplete, however compelling evidence has raised the possibility that it may be this previously unobserved state of matter. Electrons in herbertsmithite are arranged in a triangular mesh termed a Kagome lattice. Electrons in many lattices form patterns in which neighboring spins point in opposite directions; this requires that looped paths contain even numbers of atoms, so that their spins can always alternate from one to the next. Theory predicts that a Kagome lattice, which contains odd-numbered loops, can support a string-net electronic state.

Herbertsmithite has a vitreous lustre and is fairly transparent with a light-green to blue green color. Herbertsmithite has a Mohs hardness of between 3 and 3.5 and is known to have a brittle tenacity. The crystal's density has been calculated at 3.76 g/cm3.