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Lukrahnite Mineral Data
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General Lukrahnite Information
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 Chemical Formula: |
Ca(Cu,Zn)(Fe,Zn)(AsO4)2(OH,H2O)2 |
| Composition: |
Molecular Weight = 468.74 gm |
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Calcium 8.55 % Ca 11.96 % CaO |
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Zinc 6.98 % Zn 8.68 % ZnO |
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Iron 9.53 % Fe 13.63 % Fe2O3 |
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Copper 8.13 % Cu 9.16 % Cu2O |
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Arsenic 31.97 % As 49.03 % As2O5 |
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Hydrogen 0.71 % H 6.34 % H2O |
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Oxygen 34.13 % O |
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______ ______ |
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100.00 % 98.81 % = TOTAL OXIDE |
| Empirical Formula: |
CaCu0.6Zn0.5Fe3+0.8(AsO4)2(H2O)1.3(OH)0.7 |
| Environment: |
Ca analog of gartrellite. Tsumcorite group |
| IMA Status: |
Approved IMA 1999 (Dana # Added) |
| Locality: |
Tsumeb mine, Namibia. Link to MinDat.org Location Data. |
| Name Origin: |
Named for Ludger Krahn (1957-), Geologischer Dienst Nordrhein-Westfalen, geologist who provided the initial specimen for study. |
| Synonym: |
IMA1999-030 |
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Lukrahnite Crystallography
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| Axial Ratios: |
a:b:c =0.9851:1:1.3358 |
| Cell Dimensions: |
a = 5.457, b = 5.539, c = 7.399, Z = 1; alpha = 68.43°, beta = 68.9°, gamma = 69.44° V = 181.68 Den(Calc)= 4.28 |
| Crystal System: |
Triclinic - Pinacoidal H-M Symbol ( 1) Space Group: P1 |
| X Ray Diffraction: |
By Intensity(I/Io): 3.416(1)(112), 2.927(0.64)(111), 3.186(0.4)(012,102),2.533(0.3)(201,212), 2.7(0.3)(211), 2.832(0.26), 2.468(0.25), 4.953(0.22), |
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Physical Properties of Lukrahnite
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| Cleavage: |
None |
| Color: |
Yellow. |
| Diaphaneity: |
Transparent |
| Fracture: |
Brittle - Generally displayed by glasses and most non-metallic minerals. |
| Habit: |
Aggregates - Made of numerous individual crystals or clusters. |
| Habit: |
Microscopic Crystals - Crystals visible only with microscopes. |
| Habit: |
Spherical - Spherical, rounded aggregates. |
| Hardness: |
5 - Apatite |
| Luster: |
Vitreous - Adamantine |
| Streak: |
light yellow |
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Optical Properties of Lukrahnite
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| Gladstone-Dale: |
CI calc= -0.005 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2051,KC= 0.2042
Ncalc = 1.85 |
| Optical Data: |
Biaxial (+), a=1.83, b=1.834, g=1.89, bire=0.0600 |
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Calculated Properties of Lukrahnite
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| Electron Density: |
Bulk Density (Electron Density)=3.94 gm/cc
note: Specific Gravity of Lukrahnite =4.15 gm/cc.
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| Fermion Index: |
Fermion Index = 0.0051607569
Boson Index = 0.9948392431 |
| Photoelectric: |
PELukrahnite = 32.96 barns/electron
U=PELukrahnite x rElectron Density= 129.86 barns/cc.
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| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Lukrahnite is Not Radioactive |
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Lukrahnite Classification
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| Dana Class: |
43.02.02.03 (43)Compound Phosphates, etc. |
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(43.02)(Anhydrous Normal Compound Anions) |
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(43.02.02)Gartrellite Group |
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43.02.02.01 Gartrellite Pb(Cu,Fe)2(AsO4,SO4)2(CO3,H2O)0.7 P1,P 1 Tri |
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43.02.02.02 Zincgartrellite! Pb(Zn,Fe,Cu)2(AsO4)2(OH,H2O)2 P1 1 |
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43.02.02.03 Lukrahnite! Ca(Cu,Zn)(Fe,Zn)(AsO4)2(OH,H2O)2 P1 1 |
| Strunz Class: |
08.CG.20 08 - PHOSPHATES, ARSENATES, VANADATES |
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08.C - Phosphates without Additional Anions, with H2O |
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08.CG -With large and medium-sized cations, RO4:H2O = 1:1 |
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08.CG.20 Gartrellite Pb(Cu,Fe)2(AsO4,SO4)2(CO3,H2O)0.7 P1,P 1 Tri |
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08.CG.20 Helmutwinklerite PbZn2(AsO4)2•2(H2O) P1 1 |
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08.CG.20 Phosphogartrellite! PbCuFe(PO4)2(OH,H2O)2 P1 1 |
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08.CG.20 Zincgartrellite! Pb(Zn,Fe,Cu)2(AsO4)2(OH,H2O)2 P1 1 |
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08.CG.20 Rappoldite! Pb(Co,Ni,Zn,)2(AsO4)2•2(H2O) P1 1 |
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08.CG.20 Lukrahnite! Ca(Cu,Zn)(Fe,Zn)(AsO4)2(OH,H2O)2 P1 1 |
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Other Lukrahnite Information
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| References: |
NAME( AmMin, Vol 87, p 766) PHYS. PROP.(AmMin, Vol 87, p 766) OPTIC PROP.(AmMin, Vol 87, p 766) |
| See Also: |
Links to other databases for Lukrahnite :
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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Print or Cut-and-Paste your Lukrahnite Specimen Label here :
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Lukrahnite
Ca(Cu,Zn)(Fe,Zn)(AsO4)2(OH,H2O)2
Dana No: 43.02.02.03 Strunz No: 08.CG.20
Locality:
Notes:
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