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Dukeite Mineral Data

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General Dukeite Information

Help on Chemical  Formula: Chemical Formula: Bi+++24Cr++++++8O57(OH)6(H2O)3
Help on Composition: Composition: Molecular Weight = 6,499.55 gm
   Chromium   6.40 %  Cr   12.31 % CrO3
   Bismuth   77.17 %  Bi   86.03 % Bi2O3
   Hydrogen   0.19 %  H     1.66 % H2O
   Oxygen    16.25 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Bi24Cr8O57(OH)6(H2O)3
Help on Environment: Environment: Found on a specimen of pucherite.
Help on IMA Status: IMA Status: Approved IMA 1999 (Dana # Added)
Help on Locality: Locality: Found on a museum specimen labeled from the San Jose mine, Brejauba, Minas Gerais, Brazil. Corrected locality is Lavra da Posse, Sao Jose de Berjauba, Conceicao do Mato Dentro County, Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Duke University, Duham, North Carolina, USA and for the Mary Duke Biddle Foundation.
Help on Synonym: Synonym: ICSD 89799
  IMA1999-021
 

Dukeite Image

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  Dukeite

Comments: SEM photomicrograph showing part of a dukeite sheave (AmMin, 85:1823).
Location: Found on a museum specimen labeled as originating from the São José Mine, Brejaúba, Minas Gerais, Brazil. Scale: See Image.
© American Mineralogist

Dukeite Crystallography

Help on Axial Ratios: Axial Ratios: a:c = 1:1.01499
Help on Cell Dimensions: Cell Dimensions: a = 15.067, c = 15.293, Z = 2; V = 3,006.61 Den(Calc)= 7.18
Help on Crystal System: Crystal System: Trigonal - Ditrigonal Pyramidal H-M Symbol (3m) Space Group: P 31c
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.382(1), 2.681(0.7), 1.701(0.5),7.65(0.5), 2.106(0.4), 2.175(0.4), 3.812(0.4),
 

Physical Properties of Dukeite

Help on Cleavage: Cleavage: None
Help on Color: Color: Yellow, Dirty yellow brown.
Help on Diaphaneity: Diaphaneity: Translucent to transparent
Help on Fracture: Fracture: Brittle - Uneven - Very brittle fracture producing uneven fragments.
Help on Habit: Habit: Acicular - Occurs as needle-like crystals.
Help on Habit: Habit: Wheat Sheaf - Bundle shaped aggregates resembling wheat sheafs after hand reaping wheat.
Help on Hardness: Hardness: 3-4 - Calcite-Fluorite
Help on Luster: Luster: Resinous
Help on Streak: Streak: bright yellow
 

Optical Properties of Dukeite

Help on Gladstone-Dale: Gladstone-Dale: CI calc= -0.053 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.188,KC= 0.1785
Ncalc = 2.28
Help on Optical Data: Optical Data: Uniaxial (?), a=2.33, b=2.37, bire=0.0400.
Help on RL Bireflectance: RL Bireflectance: Very weak.
Help on RL Color: RL Color: Gray to purplish-gray with strong yellow internal reflections aligned with crystal direction.
Help on RL Pleochroism: RL Pleochroism: Mid orange-brown.
Help on Reflectivity Reflectivity
Standardized Intensity (100%) Reflection Spectra of Dukeite in Air
λ R1 R2  ∑ R1(λ)   ∑ R2(λ) 
 400 nm   19.80   21.40 
   
 420 nm   19.45   20.85 
 440 nm   18.90   20.05 
 460 nm   18.15   19.00 
 470 nm   17.90   18.60 
 480 nm   17.50   18.20 
 500 nm   17.00   17.55 
 520 nm   16.70   17.30 
 540 nm   16.50   17.10 
 546 nm   16.45   17.00 
 560 nm   16.30   16.90 
 580 nm   16.20   16.70 
 589 nm   16.00   16.50 
 600 nm   15.95   16.45 
 620 nm   15.80   16.25 
 640 nm   15.70   16.20 
 650 nm   15.70   16.20 
 660 nm   15.60   16.10 
 680 nm   15.50   15.95 
 700 nm   15.35   15.80 
Standardized Intensity (100%) Reflection Spectra of Dukeite in Oil
λ R1 R2  ∑ R1(λ)   ∑ R2(λ) 
 400 nm    7.60    9.01 
   
 420 nm    7.34    8.43 
 440 nm    6.80    7.61 
 460 nm    6.34    6.94 
 470 nm    6.11    6.65 
 480 nm    5.85    6.41 
 500 nm    5.48    5.98 
 520 nm    5.47    5.92 
 540 nm    5.46    5.95 
 546 nm    5.43    5.94 
 560 nm    5.32    5.88 
 580 nm    5.27    5.82 
 589 nm    5.19    5.67 
 600 nm    5.20    5.64 
 620 nm    5.12    5.64 
 640 nm    5.06    5.58 
 650 nm    5.00    5.57 
 660 nm    5.01    5.56 
 680 nm    4.95    5.56 
 700 nm    4.90    5.58 
Calculated Relative Intensity Colors of Dukeite in Air
Relative
Intensity
   0%   60% 100% 120% 180% 240% 300% 360% 420% 480% 540% 550%
R1                        
R2                        
Calculated Relative Intensity Colors of Dukeite in Oil
Relative
Intensity
   0% 100% 200% 300% 400% 500% 600% 700% 800% 900% 1000%
R1                      
R2                      
 

Calculated Properties of Dukeite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=6.02 gm/cc
note: Specific Gravity of Dukeite =7.18 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0061589959
Boson Index = 0.9938410041
Help on Photoelectric: Photoelectric: PEDukeite =1,483.23 barns/electron
U=PEDukeite x rElectron Density=8,926.62 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Dukeite is Not Radioactive
 

Dukeite Classification

Help on  Dana Class: Dana Class: 36.01.03.01 (36)Compound Chromates
  (36.01)with miscellaneous formulae
  (36.01.03)Dana Group
 
36.01.03.01 Dukeite! Bi24Cr8O57(OH)6(H2O)3 P 31c 3m
Help on  Strunz Class: Strunz Class: 07.DF.80 07 - SULFATES (SELENATES, TELLURATES)
  07.D - Sulfates (selenates, etc.) with additional anions, with H2O
  07.DF -With large and medium-sized cations
 
07.DF.80 Dukeite! Bi24Cr8O57(OH)6(H2O)3 P 31c 3m
 

Other Dukeite Information

Help on References: References: NAME( AmMin, Vol 85, p 1822) PHYS. PROP.(AmMin, Vol 85, p 1822) OPTIC PROP.(AmMin, Vol 85, p 1822)
Help on See Also: See Also: Links to other databases for Dukeite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info
11 - WWW-MINCRYST

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

Dukeite

Bi+++24Cr++++++8O57(OH)6(H2O)3
Dana No: 36.01.03.01 Strunz No: 07.DF.80
Locality:

 

Notes:

 

 
   
 


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