| Mackinawite | |
|---|---|
 | |
| General | |
| Category | Sulfide mineral |
| Formula (repeating unit) | (Fe,Ni) 1+xS (where x=0 to 0.11) |
| IMA symbol | Mkw[1] |
| Strunz classification | 2.CC.25 |
| Crystal system | Tetragonal |
| Crystal class | Ditetragonal dipyramidal (4/mmm) H-M symbol: (4/m 2/m 2/m) |
| Space group | P4/nmm |
| Unit cell | a = 3.67 Å, c = 5.03 Å; Z = 2 |
| Identification | |
| Formula mass | 85.42 g/mol |
| Color | Bronze to white grey |
| Crystal habit | As well-formed thin tabular crystals; massive, fine-feathery |
| Cleavage | Perfect on {001} |
| Mohs scale hardness | 2.5 |
| Luster | Metallic |
| Streak | Black |
| Diaphaneity | Opaque |
| Specific gravity | 4.17 |
| References | [2][3][4][5] |
Mackinawite is an iron nickel sulfide mineral with the chemical formula (Fe,Ni)
1+xS (where x = 0 to 0.11). The mineral crystallizes in the tetragonal crystal system and has been described as a distorted, close packed, cubic array of S atoms with some of the gaps filled with Fe.[6] Mackinawite 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 was first described in 1962 for an occurrence in the Mackinaw mine, Snohomish County, Washington for which it was named.[5]
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ Mineralienatlas
- ^ Handbook of Mineralogy
- ^ Webmineral data
- ^ a b Mindat
- ^ Taylor, L.A.; Finger, L.W. (1970). "Structural refinement and composition of mackinawite". Carnegie Institute of Washington Geophysical Laboratory Annual Report. 69: 318–322.