General Hilgardite Information Chemical Formula: |
Ca2B5O9Cl•(H2O) |
Composition: |
Molecular Weight = 331.67 gm |
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Calcium 24.17 % Ca 33.82 % CaO |
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Boron 16.30 % B 52.48 % B2O3 |
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Hydrogen 0.61 % H 5.43 % H2O |
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Chlorine 10.69 % Cl 10.69 % Cl |
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- %
Cl -2.41 % -O=Cl2 |
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Oxygen 48.24 % O |
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______ ______ |
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100.00 % 100.00 % = TOTAL OXIDE |
Empirical Formula: |
Ca2B5O9Cl•(H2O) |
Environment: |
Minor borate mineral in salt deposits. |
IMA Status: |
Approved IMA 1979 |
Locality: |
Choctaw Salt Dome, Iberville Parish, Louisiana, USA Link to MinDat.org Location Data. |
Name Origin: |
Named for Eugene W. Hilgard (1833-1916), German-American geologist, one of the first to describe the Loiuisiana salt dome deposits. |
Name Pronunciation: |
Hilgardite + Pronunciation |
| | Hilgardite Image
Images:
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Hilgardite Crystallography Axial Ratios: |
a:b:c =0.9741:1:1.0156 |
Cell Dimensions: |
a = 6.297, b = 6.464, c = 6.565, Z = 1; alpha = 74.24°, beta = 61.68°, gamma = 61.26° V = 198.50 Den(Calc)= 2.77 |
Crystal System: |
Triclinic - PedialH-M Symbol (1) Space Group: P1 |
X Ray Diffraction: |
By Intensity(I/Io): 2.88(1), 2.827(0.83), 2.029(0.64), |
Crystal Structure:
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Mouse
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| Physical Properties of Hilgardite Cleavage: |
{010} Perfect, {100} Perfect |
Color: |
Colorless. |
Density: |
2.69 |
Diaphaneity: |
Transparent |
Hardness: |
5 - Apatite |
Luster: |
Vitreous (Glassy) |
Streak: |
white |
| Optical Properties of Hilgardite Gladstone-Dale: |
CI meas= -0.013 (Superior) - where the CI = (1-KPDmeas/KC) |
CI calc= -0.021 (Excellent) - where the CI = (1-KPDcalc/KC) KPDcalc= 0.2409,KPDmeas= 0.2392,KC= 0.2361 Ncalc = 1.63 - 1.64 Optical Data: |
Biaxial (+), a=1.63, b=1.636, g=1.664, bire=0.0340, 2V(Calc)=52, 2V(Meas)=35. |
| Calculated Properties of Hilgardite Electron Density: |
Bulk Density (Electron Density)=2.66 gm/cc |
note: Specific Gravity of Hilgardite =2.69 gm/cc. Fermion Index: |
Fermion Index = 0.03 |
Boson Index = 0.97 Photoelectric: |
PEHilgardite = 3.87 barns/electron |
U=PEHilgardite x rElectron Density= 10.30 barns/cc. Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units) |
Hilgardite is Not Radioactive | Hilgardite Classification Dana Class: |
26.05.14.01 (26)Hydrated Borates Containing Hydroxyl or Halogen |
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(26.05)Dana Type |
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(26.05.14)Hilgardite |
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Strunz Class: |
06.ED.05 06 - BORATES |
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06.E - Pentaborates |
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06.ED -Tecto-pentaborates |
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| Other Hilgardite Information References: |
NAME( Dana8) PHYS. PROP.(Am.Min.,Vol.78,p1313,1993) OPTIC PROP.(Am.Min.,Vol.78,p1313,1993) |
See Also: |
Links to other databases for Hilgardite : |
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 13 - WWW-MINCRYST Search for Hilgardite using: Visit our Advertisers for Hilgardite : A Bijoux Google Search for HilgarditeAdam's Minerals Google Search for Hilgardite Cape Minerals Google Search for Hilgardite Dakota Matrix Minerals Google Search for Hilgardite Excalibur Mineral Corp. Google Search for Hilgardite Exceptional Minerals Google Search for Hilgardite John Betts Fine Minerals Search for Hilgardite McDougall Minerals Google Search for Hilgardite Mineral News Website Link Rock and Mineral Shows Google Search for Hilgardite Weinrich Minerals, Inc. Google Search for Hilgardite Ask about Hilgardite here : Print or Cut-and-Paste your Hilgardite Specimen Label here :
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