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Medenbachite Mineral Data

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General Medenbachite Information

Help on Chemical  Formula: Chemical Formula: Bi2Fe+++(Cu,Fe+++)(O,OH)2(OH)2(AsO4)2
Help on Composition: Composition: Molecular Weight = 879.78 gm
   Iron       7.93 %  Fe   11.34 % Fe2O3
   Copper     5.42 %  Cu    6.78 % CuO
   Bismuth   47.51 %  Bi   52.96 % Bi2O3
   Arsenic   17.03 %  As   26.12 % As2O5
   Hydrogen   0.29 %  H     2.56 % H2O
   Oxygen    21.82 %  O
            ______        ______ 
            100.00 %       99.77 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Bi2Fe3+Cu0.75Fe3+0.25O1.5(OH)2.5(AsO4)2
Help on Environment: Environment: In a silicified barite vein.
Help on IMA Status: IMA Status: Approved IMA 1993 (Dana # Added)
Help on Locality: Locality: In a quarry near the Borstein cliff, about 1 km east of the town of Reichenbach, Odenwald, Hesse, Germany. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Dr. Olaf Medenbach (1949-) of the University of Bochum, Germany.
Help on Name Pronunciation: Name Pronunciation: Medenbachite + Pronunciation Say MEDENBACHITE
Help on Synonym: Synonym: ICSD 81357
  PDF 49-1823

Medenbachite Image

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Comments: SEM image of tabular plates of mendenbachite crystals. (AmMin, v81:505).
Location: Silicified barite vein from Reichenbach near Bensheim, Odenwald, Hesse, Germany. Scale: Scale Bar 20 µm.
© American Mineralogist

Medenbachite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.7416:1:1.4594
Help on Cell Dimensions: Cell Dimensions: a = 4.57, b = 6.162, c = 8.993, Z = 1; alpha = 94.55°, beta = 99.683°, gamma = 94.283° V = 248.16 Den(Calc)= 5.89
Help on Crystal System: Crystal System: Triclinic - Pinacoidal H-M Symbol ( 1) Space Group: P1
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.749(1), 3.596(0.77), 2.903(0.69),
Help on Forms: Forms:

Dbl Clk - Start-Stop Rotation
RMB - Cycle Display Modes
Drag1 - Manipulate Crystal
Drag2 - Resize

S - Stereo
I - Indicies
<space> - Start-Stop Rotation
F - Fit to Screen
M - Menu

Help on Above

Forms: ( 1 3 1) ( 0 1 1) ( 1 1 0) ( 1 0 1) ( 0 0 1)

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Physical Properties of Medenbachite

Help on Cleavage: Cleavage: None
Help on Color: Color: Yellow, Brownish yellow.
Help on Density: Density: 5.9
Help on Diaphaneity: Diaphaneity: Transparent to translucent
Help on Fracture: Fracture: Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.
Help on Habit: Habit: Crystalline - Fine - Occurs as well-formed fine sized crystals.
Help on Habit: Habit: Tabular - Form dimensions are thin in one direction.
Help on Hardness: Hardness: 4.5 - Between Fluorite and Apatite
Help on Luster: Luster: Vitreous - Adamantine
Help on Streak: Streak: light yellow

Optical Properties of Medenbachite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.014 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.016 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1822,KPDmeas= 0.1819,KC= 0.1793
Ncalc = 2.06
Help on Optical Data: Optical Data: Biaxial (-), a=2.03, b=2.09, g=2.1, bire=0.0700, 2V(Calc)=42, 2V(Meas)=43. Dispersion r > v.

Calculated Properties of Medenbachite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=5.16 gm/cc
note: Specific Gravity of Medenbachite =5.90 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0017878211
Boson Index = 0.9982121789
Help on Photoelectric: Photoelectric: PEMedenbachite = 891.97 barns/electron
U=PEMedenbachite x rElectron Density=4,602.93 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Medenbachite is Not Radioactive

Medenbachite Classification

Help on  Dana Class: Dana Class: (41)Anhydrous Phosphates, etc. Containing Hydroxyl or Halogen
  (41.04)where (A B)5 (XO4)2 Zq
  (41.04.09)Medenbachite Group Medenbachite! Bi2Fe(Cu,Fe)(O,OH)2(OH)2(AsO4)2 P1 1 Neustadtelite! Bi2Fe(Fe,Co)(O,OH)2(OH)2(AsO4)2 P1 1 Cobaltneustadtelite! Bi2Fe(Co,Fe)(O,OH)2(OH)2(AsO4)2 P1 1
Help on  Strunz Class: Strunz Class: 08.BK.10 08 - PHOSPHATES, ARSENATES, VANADATES
  08.B - Phosphates, etc. with Additional Anions, without H2O
  08.BK -With medium-sized and large cations, (OH, etc.)
08.BK.10 Medenbachite! Bi2Fe(Cu,Fe)(O,OH)2(OH)2(AsO4)2 P1 1
08.BK.10 Cobaltneustadtelite! Bi2Fe(Co,Fe)(O,OH)2(OH)2(AsO4)2 P1 1
08.BK.10 Neustadtelite! Bi2Fe(Fe,Co)(O,OH)2(OH)2(AsO4)2 P1 1

Other Medenbachite Information

Help on References: References: NAME( MinRec) PHYS. PROP.(Am.Min.,Vol.81,1996, Vol 87, p 726) OPTIC PROP.(Am.Min.,Vol.81,1996)
Help on See Also: See Also: Links to other databases for Medenbachite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - Handbook of Mineralogy (MinSocAm)
7 - Handbook of Mineralogy (UofA)
8 - MinDAT
9 - Mineralienatlas (Deutsch)
10 - Online Mineral Museum
11 - QUT Mineral Atlas
12 - Ruff.Info

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Dana No: Strunz No: 08.BK.10





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