Nickeline
Rather rare mineral of the sulfides and sulfosalts group.
Origin of name: medieval colliers in the German Ore Mountains sometimes found a reddish, seemingly copper-bearing ore which they called "coppernickel" because they blamed their failure to extract copper from the ore on mischievous spirits, locally known as "nickel" or "nickelmen".
In 1832 French geologist and mineralogist François Sulpice Beudant coined the name nickeline, probably not after the German spirits but the Latin niccolum for nickel.
In english-speaking countries one still encounters the name niccolite, introduced in 1862 by American geologist and mineralogist James Dwight Dana. However, the IMA (International Mineralogical Association) use of the name nickeline rather than niccolite.
Synonyms and trade names: copper nickel, arsenical nickel, niccolite, nickelite
Can be confused with: pyrite and copper ores like e.g. chalcopyrite
Localities: on all continents except Antarctica. At the time of writing (2025) more than 700 localities are known, 200 of which in Germany
Handling: in Europe the use of nickel in jewellery is regulated by the Nickel Directive which imposes limits on the amount of nickel that may be released from jewellery and other products intended to come into direct and prolonged contact with the skin. With roughly 10% of the population being sensitive to nickel, the use of nickeline as a gem stone is not such a good idea after all.
Worth knowing: despite a nickel content of about 45% nickeline only plays a secondary role as a nickel ore because the arsenic as well as the very high density prove to be rather deleterious to smelting and milling.
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