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Jacobsite Mineral Data

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General Jacobsite Information

Help on Chemical  Formula: Chemical Formula: (Mn++,Fe++,Mg)(Fe+++,Mn+++)2O4
Help on Composition: Composition: Molecular Weight = 227.38 gm
   Magnesium   1.07 %  Mg    1.77 % MgO
   Manganese  26.58 %  Mn   18.72 % MnO / 17.36 % Mn2O3
   Iron       44.21 %  Fe    9.48 % FeO / 52.67 % Fe2O3
   Oxygen     28.15 %  O
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Mn2+0.6Fe2+0.3Mg0.1Fe3+1.5Mn3+0.5O4
Help on Environment: Environment: A primary mineral or and alteration product of othe rmanganese-bearing minerals in some metamorphosed Mn deposits. Dimorphous with iwakiite and forms a series with magnetite.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1869
Help on Locality: Locality: Jakobsberg, Sweden. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named after its locality.
Help on Name Pronunciation: Name Pronunciation: Jacobsite + Pronunciation Say JACOBSITE
Help on Synonym: Synonym: ICSD 28517
  PDF 74-2403
 

Jacobsite Image

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  Jacobsite   Barite

Comments: Sharp, octahedral crystals of Jacobsite on a bladed barite matrix.
Location: N' Chwaning II Mine, Kuruman, South Africa. Scale: 3x2.5x1.9 cm.
© Isaias Casanova / IC Minerals

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  Ganomalite   Jacobsite

Comments: White crystalline ganomalite with dark granular jacobsite.
Location: Jacobsberg, Varmland, Sweden. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Jacobsite Crystallography

Help on Cell Dimensions: Cell Dimensions: a = 8.499, Z = 8; V = 613.91 Den(Calc)= 4.92
Help on Crystal System: Crystal System: Isometric - Hexoctahedral H-M Symbol (4/m 3 2/m) Space Group: F d3m
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.563(1), 1.503(0.4), 3.005(0.35),
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Forms: ( 1 1 1)

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Physical Properties of Jacobsite

Help on Cleavage: Cleavage: None
Help on Color: Color: Iron black, Black.
Help on Density: Density: 4.75
Help on Diaphaneity: Diaphaneity: Opaque
Help on Fracture: Fracture: Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).
Help on Habit: Habit: Disseminated - Occurs in small, distinct particles dispersed in matrix.
Help on Habit: Habit: Massive - Granular - Common texture observed in granite and other igneous rock.
Help on Hardness: Hardness: 5.5-6 - Knife Blade-Orthoclase
Help on Luster: Luster: Sub Metallic
Help on Magnetism: Magnetism: Weakly magnetic
Help on Streak: Streak: reddish black
 

Optical Properties of Jacobsite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.01 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.044 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2642,KPDmeas= 0.2737,KC= 0.2764
Ncalc = 2.31 - 2.36
Help on Optical Data: Optical Data: Isotropic, n=2.3.
Help on RL Color: RL Color: Grayish with with olive tint and brown internal reflections.
Help on Reflectivity Reflectivity
Standardized Intensity (100%) Reflection Spectra of Jacobsite in Air
λ R  ∑ R(λ) 
 400 nm   19.00   
 420 nm   18.80 
 440 nm   18.60 
 460 nm   18.40 
 480 nm   18.20 
 500 nm   18.10 
 520 nm   18.00 
 540 nm   17.80 
 560 nm   17.60 
 580 nm   17.40 
 600 nm   17.20 
 620 nm   17.00 
 640 nm   16.80 
 660 nm   16.60 
 680 nm   16.50 
 700 nm   16.40 
Calculated Relative Intensity Colors of Jacobsite in Air
Relative
Intensity
   0%   60% 100% 120% 180% 240% 300% 360% 420% 480% 510%
R                      
 

Calculated Properties of Jacobsite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=4.49 gm/cc
note: Specific Gravity of Jacobsite =4.75 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEJacobsite = 20.56 barns/electron
U=PEJacobsite x rElectron Density= 92.33 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Jacobsite is Not Radioactive
 

Jacobsite Classification

Help on  Dana Class: Dana Class: 07.02.02.02 (07)Multiple Oxides
  (07.02)(A+ B++)2 X4 Spinel group
  (07.02.02)(Iron subgroup)
 
07.02.02.01 Magnesioferrite MgFe2O4 F d3m 4/m 3 2/m
 
07.02.02.02 Jacobsite (Mn,Fe,Mg)(Fe,Mn)2O4 F d3m 4/m 3 2/m
 
07.02.02.03 Magnetite FeFe2O4 F d3m 4/m 3 2/m
 
07.02.02.04 Franklinite (Zn,Mn,Fe)(Fe,Mn)2O4 F d3m 4/m 3 2/m
 
07.02.02.05 Trevorite NiFe2O4 F d3m 4/m 3 2/m
 
07.02.02.06 Cuprospinel (Cu,Mg)Fe2O4 F d3m 4/m 3 2/m
 
07.02.02.07 Brunogeierite (Ge,Fe)Fe2O4 F d3m 4/m 3 2/m
Help on  Strunz Class: Strunz Class: 04.BB.05 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate
  04.B - Metal:Oxygen = 3:4 and similar
  04.BB -With only medium-sized cations
 
04.BB.05 Cochromite (Co,Ni,Fe)(Cr,Al)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Filipstadite (Mn,Mg)4SbFeO8 pseudo ISO 2/m 2/m 2/m
 
04.BB.05 Magnetite FeFe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Gahnite ZnAl2O4 F d3m 4/m 3 2/m
 
04.BB.05 Chromite FeCr2O4 F d3m 4/m 3 2/m
 
04.BB.05 Galaxite (Mn,Mg)(Al,Fe)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Cuprospinel (Cu,Mg)Fe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Donathite? (Fe,Mg)(Cr,Fe)2O4 P 4/nnm 4/m 2/m 2/m
 
04.BB.05 Brunogeierite (Ge,Fe)Fe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Coulsonite FeV2O4 F d3m 4/m 3 2/m
 
04.BB.05 Hercynite FeAl2O4 F d3m 4/m 3 2/m
 
04.BB.05 Franklinite (Zn,Mn,Fe)(Fe,Mn)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Jacobsite (Mn,Fe,Mg)(Fe,Mn)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Magnesiochromite MgCr2O4 F d3m 4/m 3 2/m
 
04.BB.05 Magnesioferrite MgFe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Magnesiocoulsonite MgV2O4 F d3m 4/m 3 2/m
 
04.BB.05 Manganochromite (Mn,Fe)(Cr,V)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Qandilite (Mg,Fe)2(Ti,Fe,Al)O4 F d3m 4/m 3 2/m
 
04.BB.05 Nichromite (Ni,Co,Fe)(Cr,Fe,Al)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Spinel MgAl2O4 F d3m 4/m 3 2/m
 
04.BB.05 Ulvospinel TiFe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Zincochromite ZnCr2O4 F d3m 4/m 3 2/m
 
04.BB.05 Trevorite NiFe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Vuorelainenite (Mn,Fe)(V,Cr)2O4 F d3m 4/m 3 2/m
 

Other Jacobsite Information

Help on References: References: NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic3)
Help on See Also: See Also: Links to other databases for Jacobsite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - Franklin Minerals(Dunn)
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - QUT Mineral Atlas
15 - Ruff.Info
16 - University of Colorado - Mineral Structure Data
17 - WWW-MINCRYST

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Print or Cut-and-Paste your Jacobsite Specimen Label here :

Jacobsite

(Mn++,Fe++,Mg)(Fe+++,Mn+++)2O4
Dana No: 07.02.02.02 Strunz No: 04.BB.05
Locality:

 

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