Herbertsmithite

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Herbertsmithite
Category	Copper minerals Zinc minerals Halide minerals
Chemical formula	Zn Cu₃(OH)₆Cl₂
Identification
Color	Light green, blue-green
Crystal system	Trigonal
Cleavage	Distinct to good
Tenacity	Brittle
Mohs Scale hardness	3-3½
Luster	Vitreous
Streak	Light green
Density	3.76
Diaphaneity	Transparent

Herbertsmithite is a mineral with chemical structure Zn Cu₃(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.