General Magnesiohornblende Information Chemical Formula: |
Ca2[Mg4(Al,Fe+++)]Si7AlO22(OH)2 |
Composition: |
Molecular Weight = 821.16 gm |
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Calcium 9.76 % Ca 13.66 % CaO |
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Magnesium 11.84 % Mg 19.63 % MgO |
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Aluminum 5.75 % Al 10.86 % Al2O3 |
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Iron 1.70 % Fe 2.43 % Fe2O3 |
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Silicon 23.94 % Si 51.22 % SiO2 |
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Hydrogen 0.25 % H 2.19 % H2O |
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Oxygen 46.76 % O |
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______ ______ |
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100.00 % 100.00 % = TOTAL OXIDE |
Empirical Formula: |
Ca2Mg4Al0.75Fe3+0.25(Si7AlO22)(OH)2 |
Environment: |
Igneous and metamorphic rocks. |
IMA Status: |
Approved IMA 1978 |
Locality: |
Probably common worldwide in "hornblende" granites and shists. Link to MinDat.org Location Data. |
Name Origin: |
Named for the composition and its relationship to hornblende. |
Synonym: |
Aluminomagnesiohornblende |
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Hornblende |
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ICSD 79834 |
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PDF 45-1371 |
| | Magnesiohornblende Image
Images:
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Magnesiohornblende Crystallography Axial Ratios: |
a:b:c =0.544:1:0.292 |
Cell Dimensions: |
a = 9.887, b = 18.174, c = 5.308, Z = 2; beta = 105° V = 921.28 Den(Calc)= 2.96 |
Crystal System: |
Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/m |
X Ray Diffraction: |
By Intensity(I/Io): 3.14(1), 8.51(0.55), 2.72(0.35), |
Crystal Structure:
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Mouse
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| Physical Properties of Magnesiohornblende Cleavage: |
{???} Perfect, {???} Distinct |
Color: |
Brown, Green, Greenish brown, Greenish black, Dark green. |
Density: |
3 - 3.47, Average = 3.23 |
Diaphaneity: |
Translucent to opaque |
Fracture: |
Sub Conchoidal - Fractures developed in brittle materials characterized by semi-curving surfaces. |
Habit: |
Columnar - Forms columns |
Habit: |
Massive - Fibrous - Distinctly fibrous fine-grained forms. |
Habit: |
Massive - Granular - Common texture observed in granite and other igneous rock. |
Hardness: |
5-6 - Between Apatite and Orthoclase |
Luminescence: |
Non-fluorescent. |
Luster: |
Vitreous - Pearly |
Streak: |
white |
| Optical Properties of Magnesiohornblende Gladstone-Dale: |
CI meas= 0.04 (Good) - where the CI = (1-KPDmeas/KC) |
CI calc= -0.049 (Good) - where the CI = (1-KPDcalc/KC) KPDcalc= 0.2226,KPDmeas= 0.2037,KC= 0.2121 Ncalc = 1.63 - 1.74 Optical Data: |
Biaxial (-), a=1.616-1.68, b=1.626-1.695, g=1.636-1.7, bire=0.0200, 2V(Calc)=58-88, 2V(Meas)=66-85. Dispersion r > v or r < v. |
Pleochroism (x): |
light green, yellowish green, yellow, greenish brown, or yellow. |
Pleochroism (y): |
dark green, dark yellowish green, brown. Pale, reddish brown, or greenish yellow. |
| Calculated Properties of Magnesiohornblende Electron Density: |
Bulk Density (Electron Density)=3.22 gm/cc |
note: Specific Gravity of Magnesiohornblende =3.24 gm/cc. Fermion Index: |
Fermion Index = 0.02 |
Boson Index = 0.98 Photoelectric: |
PEMagnesiohornblende = 3.05 barns/electron |
U=PEMagnesiohornblende x rElectron Density= 9.83 barns/cc. Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units) |
Magnesiohornblende is Not Radioactive | Magnesiohornblende Classification Dana Class: |
66.01.03a.04 (66)Inosilicate Double-Width Unbranched Chains, W=2 |
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(66.01)with P=2 amphibole configuration |
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(66.01.03a)Group 2, the calcic amphiboles |
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Strunz Class: |
09.DE.10 09 - SILICATES (Germanates) |
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09.D - Inosilicates* Structural terminology according to Liebau (1985) |
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09.DE -Inosilicates with 2-periodic double chains, Si4O11; amphibole family |
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| Other Magnesiohornblende Information See Also: |
Links to other databases for Magnesiohornblende : |
1 - Alkali-Nuts(English) 2 - Alkali-Nuts(Francais) 3 - Am. Min. Crystal Structure Database 4 - Athena 5 - EUROmin Project 6 - Ecole des Mines de Paris 7 - Franklin Minerals(Dunn) 8 - GeoScienceWorld 9 - Google Images 10 - Google Scholar 11 - Handbook of Mineralogy (MinSocAm) 12 - Handbook of Mineralogy (UofA) 13 - MinDAT 14 - Mineralienatlas (Deutsch) 15 - Online Mineral Museum 16 - QUT Mineral Atlas 17 - Ruff.Info Search for Magnesiohornblende using: Visit our Advertisers for Magnesiohornblende : A Bijoux Google Search for MagnesiohornblendeAdam's Minerals Google Search for Magnesiohornblende Cape Minerals Google Search for Magnesiohornblende Dakota Matrix Minerals Google Search for Magnesiohornblende Excalibur Mineral Corp. Google Search for Magnesiohornblende Exceptional Minerals Google Search for Magnesiohornblende John Betts Fine Minerals Search for Magnesiohornblende McDougall Minerals Google Search for Magnesiohornblende Mineral News Website Link Rock and Mineral Shows Google Search for Magnesiohornblende Weinrich Minerals, Inc. Google Search for Magnesiohornblende Ask about Magnesiohornblende here : Print or Cut-and-Paste your Magnesiohornblende Specimen Label here :
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