Mineralogy Database

Mackinawite Mineral Data

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General Mackinawite Information

Help on Chemical  Formula: Chemical Formula: (Fe,Ni)S0.9
Help on Composition: Composition: Molecular Weight = 85.42 gm
   Iron    49.04 %  Fe
   Nickel  17.18 %  Ni
   Sulfur  33.79 %  S
          100.00 % 
Help on Empirical Formula: Empirical Formula: Fe2+0.75Ni0.25S0.9
Help on Environment: Environment: Serpentinization of ultrabasic rocks.
Help on IMA Status: IMA Status: Approved IMA 1962
Help on Locality: Locality: Mackinaw mine, Snohomish County, Washington, USA. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for the locality.
Help on Name Pronunciation: Name Pronunciation: Mackinawite + Pronunciation Say MACKINAWITE
Help on Synonym: Synonym: ICSD 81087
  PDF 24-73

Mackinawite Image

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Comments: Mackinawite inclusions in sulfide ore (polished specimen).
Location: Mackinaw Mine, Snohomish County, Washington, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Mackinawite Crystallography

Help on Axial Ratios: Axial Ratios: a:c = 1:1.36887
Help on Cell Dimensions: Cell Dimensions: a = 3.676, c = 5.032, Z = 2; V = 68.00 Den(Calc)= 4.17
Help on Crystal System: Crystal System: Tetragonal - Ditetragonal Dipyramidal H-M Symbol (4/m 2/m 2/m) Space Group: P 4/nmm
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 5.03(1), 2.31(0.8), 2.97(0.8),

Physical Properties of Mackinawite

Help on Cleavage: Cleavage: {001} Perfect
Help on Color: Color: Bronze, White gray.
Help on Diaphaneity: Diaphaneity: Opaque
Help on Habit: Habit: Anhedral Grains - Granular minerals without the expression of crystal shapes
Help on Habit: Habit: Microscopic Crystals - Crystals visible only with microscopes.
Help on Hardness: Hardness: 2.5 - Finger Nail
Help on Luster: Luster: Metallic
Help on Streak: Streak: black

Optical Properties of Mackinawite

Help on RL Anisotrophism: RL Anisotrophism: Extreme.
Help on RL Pleochroism: RL Pleochroism: Strong.
Help on Reflectivity Reflectivity
Standardized Intensity (100%) Reflection Spectra of Mackinawite in Air
λ R1 R2  ∑ R1(λ)   ∑ R2(λ) 
 400 nm   21.00   35.50 
 420 nm   21.00   37.20 
 440 nm   21.00   38.90 
 460 nm   21.00   40.40 
 480 nm   21.10   41.80 
 500 nm   21.20   43.10 
 520 nm   21.30   44.30 
 540 nm   21.60   45.30 
 560 nm   21.90   46.10 
 580 nm   22.20   46.90 
 600 nm   22.60   47.40 
 620 nm   22.90   47.80 
 640 nm   23.30   48.20 
 660 nm   23.80   48.50 
 680 nm   24.30   48.80 
 700 nm   24.90   49.10 
Calculated Relative Intensity Colors of Mackinawite in Air
   0%   50% 100% 150% 200% 250% 300% 350% 400% 420%

Calculated Properties of Mackinawite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.99 gm/cc
note: Specific Gravity of Mackinawite =4.17 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEMackinawite = 23.63 barns/electron
U=PEMackinawite x rElectron Density= 94.38 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Mackinawite is Not Radioactive

Mackinawite Classification

Help on  Dana Class: Dana Class: (02)Sulfides - Including Selenides and Tellurides
  (02.07)where Am Bn Xp, with (m+n):p=9:8
  (02.07.02)Dana Group Mackinawite (Fe,Ni)S0.9 P 4/nmm 4/m 2/m 2/m Sugakiite! Cu(Fe,Ni)8S8 P 41/mnm 4/m 2/m 2/m
Help on  Strunz Class: Strunz Class: 02.CC.25 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf
  02.C - Metal Sulfides, M:S = 1:1 (and similar)
  02.CC -With Ni, Fe, Co, PGE, etc.
02.CC.25 Mackinawite (Fe,Ni)S0.9 P 4/nmm 4/m 2/m 2/m

Other Mackinawite Information

Help on References: References: PHYS. PROP.(Dana8) OPTIC PROP.(AntBidBlaNic1)
Help on See Also: See Also: Links to other databases for Mackinawite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

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Dana No: Strunz No: 02.CC.25





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