My watch list  


Chemical formula(Fe,Ni)9S8
Molecular Weight85.42 gm
ColorBronze to white Grey
Crystal habitAnhedral grains to microscopic crystals
Crystal systemTetragonal
CleavagePrefect on the [001]
Mohs Scale hardness2.5
Density4.17 g/cm3

Mackinawite is an iron nickel sulfide mineral with formula (Fe,Ni)1 + xS (where x = 0 to 0.11). It crystallizes in the tetragonal crystal system and occurs as opaque bronze to grey-white tabular crystals and anhedral masses. It has a Mohs hardness of 2.5 and a specific gravity of 4.17.

It occurs in serpentinized peridotites as a hydrothermal alteration product. It also is found in the reducing environment of fine grained river sediments, possibly produced by the action of magnetotactic and sulfate-reducing bacteria. It has also been reported from meteorite occurrences.

It was first described in 1962 for an occurrence in the Mackinaw mine, Snohomish County, Washington for which it was named.


  • Handbook of Mineralogy
  • Webmineral data
  • Mindat
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Mackinawite". A list of authors is available in Wikipedia.
Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE