Ullmannite

Ullmannite is a nickel antimony sulfide mineral with formula: (NiSbS). Considerable substitution occurs with cobalt and iron in the nickel site along with bismuth and arsenic in the antimony site. A solid solution series exists with the high cobalt willyamite. It is steel-gray to tin white in colour with a metallic luster. It has a Mohs hardness of 5 to 5.5 and a specific gravity of 6.65. It crystallizes in the isometric crystal class and typically exhibits cubic, octahedral, or pyritohedral forms although euhedral crystals are rare. Crystal twinning is common.

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Principal localities are in Germany, it is also found in Austria, Australia, France, England, and Wales.

It was discovered in 1843 at the Storch und Schöneberg Mine, North Rhine-Westphalia, Germany and named for the German chemist and mineralogist, Johann Christoph Ullmann (1771-1821).

See also

• List of minerals
• List of minerals named after people

References

• Palache, C., H. Berman, and C. Frondel (1944) Dana’s system of mineralogy, (7th edition), v. I, 301–302.
• Mineral Data Publishing, PDF
• Webmineral data
• Mindat with location data