Mohawkite is a rare rock consisting of mixtures of

arsenic Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, ...

, silver, nickel, skutterudite and

copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...

, with the formula Cu₃As up to Cu₆As, and the most desirable material was usually found in white

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...

matrix. It has a

hardness In materials science, hardness (antonym: softness) is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. In general, different materials differ in their hardness; for example hard ...

of 3-3.5 and a metallic luster. It is named after the Mohawk mine where it was originally found. Colors range from brassy-yellow to metallic gray, and sometimes will have a blue or greenish surface tarnish. These colors come from its two main ingredients, the arsenic-rich copper minerals

algodonite Algodonite is a copper arsenide mineral with formula: Cu6As. It is a gray white metallic mineral crystallizing in the hexagonal system. It has a Mohs hardness of 4 and a specific gravity of 8.38 - 8.72. It was first described in 1857 from the Alg ...

and

domeykite Domeykite is a copper arsenide mineral, Cu3As. It crystallizes in the isometric system, although crystals are very rare. It typically forms as irregular masses or botryoidal forms. It is an opaque, white to gray (weathers brassy) metallic minera ...

. Its color may resemble

pyrrhotite Pyrrhotite is an iron sulfide mineral with the formula Fe(1-x)S (x = 0 to 0.2). It is a nonstoichiometric variant of FeS, the mineral known as troilite. Pyrrhotite is also called magnetic pyrite, because the color is similar to pyrite and it i ...

, but unlike pyrrhotite, mohawkite is not magnetic.Lynch, Dan R., and Bob Lynch. "Mohawkite." Michigan Rocks & Minerals. Ed. Brett Ortler. N.p.: Adventure Publications, n.d. N. pag. Print.

Etymology and origin

Mohawkite is believed to be found only in a copper mine located on the Keweenaw Peninsula of

Michigan Michigan () is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the List of U.S. states and ...

, known as the Mohawk Mine. The Mohawk Mine is where mohawkite was first discovered, in January 1900, near No. 1 shaft when a fissure vein of copper

ore Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 Apr ...

was cut. Specimens of this ore were sent to George A Koenig, of the Michigan College of Mines (now known as Michigan Technological University) for analysis. The ore was believed to be an entirely new mineral and was named mohawkite by Koenig. A reanalysis of the material in 1971 found it to be an intimate mixture of copper and nickel arsenides and the mohawkite name was discredited as a mineral species.Moore, Paul B.; ''Copper-Nickel Arsenides of the Mohawk No. 2 Mine, Mohawk, Keweenaw Co., Michigan,'' American Mineralogist, V. 56, July-August, 197
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Uses

Mohawkite, being a copper ore, is used for obtaining copper. However, when the copper is removed, it is

toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subs ...

due to the amounts of arsenic in it. Mohawkite, particularly when it contains quartz, is often used in

jewelry Jewellery ( UK) or jewelry ( U.S.) consists of decorative items worn for personal adornment, such as brooches, rings, necklaces, earrings, pendants, bracelets, and cufflinks. Jewellery may be attached to the body or the clothes. From a w ...

because of its appearance.

References

External links

{{wiktionary
Mohawkite
a
Mindat
Rocks Geology of Michigan

Etymology and origin

Uses

See also

References

External links