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Cerchiaraite Mineral Data
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General Cerchiaraite Information
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 Chemical Formula: |
Ba4(Mn,Fe,Al)4Si6(O,OH,Cl)26 |
| Composition: |
Molecular Weight = 1,398.66 gm |
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Barium 39.27 % Ba 43.85 % BaO |
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Manganese 13.35 % Mn 17.24 % MnO |
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Aluminum 0.58 % Al 1.09 % Al2O3 |
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Iron 1.60 % Fe 2.05 % FeO |
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Silicon 12.05 % Si 25.77 % SiO2 |
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Hydrogen 0.52 % H 4.64 % H2O |
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Chlorine 3.80 % Cl 3.80 % Cl |
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- %
Cl -0.86 % -O=Cl2 |
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Oxygen 28.83 % O |
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______ ______ |
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100.00 % 97.60 % = TOTAL OXIDE |
| Empirical Formula: |
Ba4Mn2+3.4Fe2+0.4Al0.3Si6O18(OH)7.2Cl1.5 |
| Environment: |
Individual grains in fractures. |
| IMA Status: |
Approved IMA 1999 (Dana # Added) |
| Locality: |
Cerchiara manganese (braunite) mine, Val di Vara, eastern Liguria, Italy. Link to MinDat.org Location Data. |
| Name Origin: |
Named for the locality. |
| Synonym: |
IMA1999-012 |
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Cerchiaraite Image |
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Images:
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Cerchiaraite Crystallography
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| Axial Ratios: |
a:c = 1:0.43095 |
| Cell Dimensions: |
a = 14.215, c = 6.126, Z = 2; V = 1,237.86 Den(Calc)= 3.75 |
| Crystal System: |
Tetragonal - Ditetragonal Dipyramidal H-M Symbol (4/m 2/m 2/m) Space Group: I 4/mmm |
| X Ray Diffraction: |
By Intensity(I/Io): 3.011(1)(411), 10.15(0.88)(110), 3.319(0.75)(321),2.619(0.74)(222), 2.577(0.62)(501), 5.63(0.5)(101), 4.417(0.49)(211), |
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Physical Properties of Cerchiaraite
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| Cleavage: |
None |
| Color: |
Deep green. |
| Diaphaneity: |
Transparent |
| Fracture: |
Brittle - Uneven - Very brittle fracture producing uneven fragments. |
| Habit: |
Granular - Generally occurs as anhedral to subhedral crystals in matrix. |
| Habit: |
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline). |
| Habit: |
Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite) |
| Hardness: |
4-5 - Fluorite-Apatite |
| Luster: |
Vitreous (Glassy) |
| Streak: |
pale green |
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Optical Properties of Cerchiaraite
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| Gladstone-Dale: |
CI calc= -0.134 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2013,KC= 0.1776
Ncalc = 1.67 |
| Optical Data: |
Uniaxial (+), w=1.745, e=1.765, bire=0.0200. |
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Calculated Properties of Cerchiaraite
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| Electron Density: |
Bulk Density (Electron Density)=3.44 gm/cc
note: Specific Gravity of Cerchiaraite =3.75 gm/cc.
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| Fermion Index: |
Fermion Index = 0.07
Boson Index = 0.93 |
| Photoelectric: |
PECerchiaraite = 176.49 barns/electron
U=PECerchiaraite x rElectron Density= 607.19 barns/cc.
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| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Cerchiaraite is Not Radioactive |
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Cerchiaraite Classification
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| Dana Class: |
62.01.01.02 (62)Cyclosilicate Eight-Membered Rings |
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(62.01)with 8-memebered and larger rings |
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(62.01.01)Muirite Group |
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62.01.01.01 Muirite Ba10Ca2MnTiSi10O30(OH,Cl,F)10 P 4/mmm 4/m 2/m 2/m |
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62.01.01.02 Cerchiaraite! Ba4(Mn,Fe,Al)4Si6(O,OH,Cl)26 I 4/mmm 4/m 2/m 2/m |
| Strunz Class: |
09.CF.25 09 - SILICATES (Germanates) |
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09.C - Cyclosilicates |
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09.CF -[Si4O12]8- 4-membered single rings, with insular complex anions |
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09.CF.25 Cerchiaraite! Ba4(Mn,Fe,Al)4Si6(O,OH,Cl)26 I 4/mmm 4/m 2/m 2/m |
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Other Cerchiaraite Information
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| References: |
NAME( AmMin, Vol 86) PHYS. PROP.(AmMin, Vol 86) OPTIC PROP.(AmMin, Vol 86) |
| See Also: |
Links to other databases for Cerchiaraite :
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
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Print or Cut-and-Paste your Cerchiaraite Specimen Label here :
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Cerchiaraite
Ba4(Mn,Fe,Al)4Si6(O,OH,Cl)26
Dana No: 62.01.01.02 Strunz No: 09.CF.25
Locality:
Notes:
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