General Jahnsite-(CaMnMg) Information Chemical Formula: |
CaMnMg2Fe+++2(PO4)4(OH)2•8(H2O) |
Composition: |
Molecular Weight = 813.34 gm |
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Calcium 4.93 % Ca 6.89 % CaO |
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Magnesium 5.98 % Mg 9.91 % MgO |
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Manganese 6.75 % Mn 8.72 % MnO |
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Iron 13.73 % Fe 19.63 % Fe2O3 |
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Phosphorus 15.23 % P 34.90 % P2O5 |
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Hydrogen 2.23 % H 19.93 % H2O |
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Oxygen 51.15 % O |
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______ ______ |
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100.00 % 100.00 % = TOTAL OXIDE |
Empirical Formula: |
CaMn2+Mg2Fe3+2(PO4)4(OH)2•8(H2O) |
IMA Status: |
Approved IMA 1974 |
Locality: |
Tip Top pegmatite, Custer, South Dakota, USA. Link to MinDat.org Location Data. |
Name Origin: |
Named for Richard H. Jahns (1915-1983), mineralogist and pegmatite expert, Stanford University, Palo Alto, California, USA. |
Name Pronunciation: |
Jahnsite-(CaMnMg) |
Synonym: |
Jahnsite |
| | Jahnsite-(CaMnMg) Image
Images:
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Jahnsite-(CaMnMg) Crystallography Axial Ratios: |
a:b:c =2.0924:1:1.3907 |
Cell Dimensions: |
a = 14.94, b = 7.14, c = 9.93, Z = 2; beta = 110.68° V = 991.00 Den(Calc)= 2.73 |
Crystal System: |
Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2/a |
X Ray Diffraction: |
By Intensity(I/Io): 9.27(1), 2.825(0.8), 4.91(0.6), |
Crystal Structure:
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Mouse
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| Physical Properties of Jahnsite-(CaMnMg) Cleavage: |
{001} Good |
Color: |
Brown, Purplish brown, Yellow, Yellow orange, Greenish yellow. |
Density: |
2.706 - 2.718, Average = 2.71 |
Diaphaneity: |
Transparent to Translucent |
Fracture: |
Brittle - Generally displayed by glasses and most non-metallic minerals. |
Hardness: |
4 - Fluorite |
Luster: |
Vitreous - Adamantine |
Streak: |
white |
| Optical Properties of Jahnsite-(CaMnMg) Gladstone-Dale: |
CI meas= 0.013 (Superior) - where the CI = (1-KPDmeas/KC) |
CI calc= 0.019 (Excellent) - where the CI = (1-KPDcalc/KC) KPDcalc= 0.2403,KPDmeas= 0.2419,KC= 0.245 Ncalc = 1.66 - 1.67 Optical Data: |
Biaxial (+), a=1.64, b=1.658, g=1.67, bire=0.0300 |
Pleochroism (x): |
pale purple. |
Pleochroism (y): |
deep purplish brown. |
Pleochroism (z): |
greenish yellow. |
| Calculated Properties of Jahnsite-(CaMnMg) Electron Density: |
Bulk Density (Electron Density)=2.71 gm/cc |
note: Specific Gravity of Jahnsite-(CaMnMg) =2.71 gm/cc. Fermion Index: |
Fermion Index = 0.0092032727 |
Boson Index = 0.9907967273 Photoelectric: |
PEJahnsite-(CaMnMg) = 7.19 barns/electron |
U=PEJahnsite-(CaMnMg) x rElectron Density= 19.50 barns/cc. Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units) |
Jahnsite-(CaMnMg) is Not Radioactive | Jahnsite-(CaMnMg) Classification Dana Class: |
42.11.02.01 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen |
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(42.11)where (AB)4 (XO4)3 Zq · x(H2O) |
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(42.11.02)Jahnsite Group |
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Strunz Class: |
08.DH.15 08 - PHOSPHATES, ARSENATES, VANADATES |
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08.D - Phosphates, etc |
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08.DH -With large and medium-sized cations, (OH, etc.):RO4 < 1:1 |
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| Other Jahnsite-(CaMnMg) Information References: |
NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8) |
See Also: |
Links to other databases for Jahnsite-(CaMnMg) : |
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 Search for Jahnsite-(CaMnMg) using: Visit our Advertisers for Jahnsite-(CaMnMg) : A Bijoux Google Search for Jahnsite-(CaMnMg)Adam's Minerals Google Search for Jahnsite-(CaMnMg) Cape Minerals Google Search for Jahnsite-(CaMnMg) Dakota Matrix Minerals Google Search for Jahnsite-(CaMnMg) Excalibur Mineral Corp. Google Search for Jahnsite-(CaMnMg) Exceptional Minerals Google Search for Jahnsite-(CaMnMg) John Betts Fine Minerals Search for Jahnsite-(CaMnMg) McDougall Minerals Google Search for Jahnsite-(CaMnMg) Mineral News Website Link Rock and Mineral Shows Google Search for Jahnsite-(CaMnMg) Weinrich Minerals, Inc. Google Search for Jahnsite-(CaMnMg) Ask about Jahnsite-(CaMnMg) here : Print or Cut-and-Paste your Jahnsite-(CaMnMg) Specimen Label here :
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