Mineralogy Database

Modderite Mineral Data

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General Modderite Information

Help on Chemical  Formula: Chemical Formula: (Co,Fe)As
Help on Composition: Composition: Molecular Weight = 133.08 gm
   Iron     10.49 %  Fe
   Cobalt   33.21 %  Co
   Arsenic  56.30 %  As
           100.00 % 
Help on Empirical Formula: Empirical Formula: Co0.75Fe2+0.25As
Help on Environment: Environment: In heavy mineral concentrates.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1924
Help on Locality: Locality: Modderfontein mine, Witwatersrand, Transvaal, South Africa. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for the locality.
Help on Name Pronunciation: Name Pronunciation: Modderite + Pronunciation Say MODDERITE
Help on Synonym: Synonym: ICSD 48026
  PDF Sep-94

Modderite Image

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Comments: Synthetic crystal of modderite grown for study of this extremely rare mineral.
Location: None, grown in a laboratory. Scale: Grain size 100 µ-m.
© Katie Phillips / Vassar College

Modderite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.5891:1:0.9016
Help on Cell Dimensions: Cell Dimensions: a = 3.458, b = 5.869, c = 5.292, Z = 4; V = 107.40 Den(Calc)= 8.23
Help on Crystal System: Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pmcn
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 12.1(1), 2.46(0.9), 4.48(0.8),

Physical Properties of Modderite

Help on Color: Color: Bluish white, Steel gray.
Help on Diaphaneity: Diaphaneity: Opaque
Help on Habit: Habit: Granular - Generally occurs as anhedral to subhedral crystals in matrix.
Help on Habit: Habit: Microscopic Crystals - Crystals visible only with microscopes.
Help on Hardness: Hardness: 4 - Fluorite
Help on Luster: Luster: Metallic
Help on Streak: Streak: gray

Calculated Properties of Modderite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=7.39 gm/cc
note: Specific Gravity of Modderite =8.23 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0022240898
Boson Index = 0.9977759102
Help on Photoelectric: Photoelectric: PEModderite = 55.86 barns/electron
U=PEModderite x rElectron Density= 412.81 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Modderite is Not Radioactive

Modderite Classification

Help on  Dana Class: Dana Class: (02)Sulfides - Including Selenides and Tellurides
  (02.08)where Am Bn Xp, with (m+n):p=1:1
  (02.08.18)Dana Group Modderite (Co,Fe)As Pmcn 2/m 2/m 2/m
Help on  Strunz Class: Strunz Class: 02.CC.15 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.15 Cherepanovite RhAs P nma 2/m 2/m 2/m
02.CC.15 Modderite (Co,Fe)As Pmcn 2/m 2/m 2/m
02.CC.15 Ruthenarsenite (Ru,Ni)As P nma 2/m 2/m 2/m
02.CC.15 Westerveldite (Fe,Ni,Co)As Pnam 2/m 2/m 2/m

Other Modderite Information

Help on References: References: NAME( AntBidBlaNic1) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990)
Help on See Also: See Also: Links to other databases for Modderite :
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.15





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