General Piemontite Information
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Chemical Formula: |
Ca2(Al,Mn,Fe)3(SiO4)3(OH) = Ca2(Mn,Fe)Al2(SiO4)(Si2O7)O(OH) |
Composition: |
Molecular Weight = 488.18 gm |
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Calcium 16.42 % Ca 22.97 % CaO |
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Manganese 10.13 % Mn 13.08 % MnO |
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Aluminum 9.95 % Al 18.80 % Al2O3 |
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Iron 3.43 % Fe 4.42 % FeO |
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Silicon 17.26 % Si 36.92 % SiO2 |
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Hydrogen 0.21 % H 1.85 % H2O |
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Oxygen 42.61 % O |
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______ ______ |
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100.00 % 98.03 % = TOTAL OXIDE |
Empirical Formula: |
Ca2Al1.8Mn2+0.9Fe2+0.3(SiO4)3(OH) |
Environment: |
Contact metamorphic rocks. |
IMA Status: |
Valid Species (Pre-IMA) 1853 |
Locality: |
Piedmont, Italy. Link to MinDat.org Location Data. |
Name Origin: |
Named after its locality. |
Synonym: |
Piedmontite |
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Piemontite Image |
Images:
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Piemontite Crystallography
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Axial Ratios: |
a:b:c =1.5609:1:1.7917 |
Cell Dimensions: |
a = 8.843, b = 5.665, c = 10.15, Z = 2; beta = 115.4° V = 459.32 Den(Calc)= 3.53 |
Crystal System: |
Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 21/m |
X Ray Diffraction: |
By Intensity(I/Io): 2.903(1), 2.598(0.5), 4(0.5), |
Crystal Structure:
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Dollase W A , American Mineralogist , 54 (1969) p.710-717, Crystal structure and cation ordering of piemontite
View Additional jPOWD Structure files for Piemontite
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Physical Properties of Piemontite
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Cleavage: |
[001] Good, [100] Distinct |
Color: |
Yellow, Carmine red, Red, Reddish brown, Reddish black. |
Density: |
3.4 |
Diaphaniety: |
Translucent |
Fracture: |
Splintery - Thin, elongated fractures produced by intersecting good cleavages or partings (e.g. hornblende). |
Habit: |
Blocky - Crystal shape tends to be equant (e.g. feldspars). |
Habit: |
Massive - Granular - Common texture observed in granite and other igneous rock. |
Habit: |
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline). |
Hardness: |
6-7 - Orthoclase-Quartz |
Luminescence: |
Non-fluorescent. |
Luster: |
Vitreous (Glassy) |
Magnetism: |
Nonmagnetic |
Streak: |
red |
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Optical Properties of Piemontite
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Gladstone-Dale: |
CI meas= -0.099 (Poor) - where the CI = (1-KPDmeas/KC) CI calc= -0.059 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2163,KPDmeas= 0.2246,KC= 0.2043 |
Optical Data: |
Biaxial (+), a=1.725-1.756, b=1.73-1.789, g=1.75-1.832, bire=0.0250-0.0760, 2V(Calc)=54-86, 2V(Meas)=50-86. Dispersion strong, r > v. |
Pleochroism (x): |
pale yellow, yellow, lemon yellow, orange, or red. |
Pleochroism (y): |
pale purple, amethyst violet, violet, rose, or deep red. |
Pleochroism (z): |
deep purple red, brownish red, carmine red, bright rose, or pink. |
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Calculated Properties of Piemontite
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Electron Density: |
relectron=3.48 gm/cc note: rPiemontite =3.53 gm/cc. |
Fermion Index |
Fermion Index = 0.00921 Boson Index = 0.99079 |
Photoelectric: |
PEPiemontite = 6.55 barns/electron U=PEPiemontite x relectron= 22.82 barns/cc. |
Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Piemontite is Not Radioactive |
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Piemontite Classification
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Dana Class: |
58.2.1a.11 (58)Sorosilicate Insular, Mixed, Single, and Larger Tetrahedral Groups |
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(58.2)with cations in [6] and higher coordination; single and double groups (n=1,2) |
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(58.2.1a)Epidote group (Epidote subgroup) |
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58.2.1a.1 Allanite-(Ce) (Ce,Ca,Y)2(Al,Fe)3(SiO4)3(OH) P 21/m 2/m |
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58.2.1a.2 Allanite-(La)! Ca(REE,Ca)Al2(Fe,Fe)(SiO4)(Si2O7)O(OH) P 21/m 2/m |
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58.2.1a.3 Allanite-(Y) (Y,Ce,Ca)2(Al,Fe)3(SiO4)3(OH) P 21/m 2/m |
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58.2.1a.4 Clinozoisite Ca2Al3(SiO4)3(OH)=Ca2AlAl2(SiO4)(Si2O7)O(OH) P 21/m 2/m |
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58.2.1a.5 Dissakisite-(Ce) Ca(Ce,REE)(Mg,Fe)(Al,Fe)2Si3O12(OH) P 21/m 2/m |
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58.2.1a.6 Dollaseite-(Ce) CaCeMg2AlSi3O11(OH,F)2 P 21/m 2/m |
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58.2.1a.7 Epidote Ca2(Fe,Al)3(SiO4)3(OH)=Ca2(Fe,Al)Al2(SiO4)(Si2O7)O(OH) P 21/m 2/m |
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58.2.1a.8 Hancockite (Ca,Pb,Sr)2(Al,Fe)3(SiO4)(Si2O7)O(OH) P 21/m 2/m |
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58.2.1a.9 Khristovite-(Ce) (Ca,REE)(Ce,REE)(Mg,Fe,Cr,Ti,V,Al)MnAl(SiO4)(Si2O7)(OH)(F,O) P 21/m 2/m |
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58.2.1a.10 Mukhinite Ca2Al2V(SiO4)3(OH) P 21/m 2/m |
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58.2.1a.11 Piemontite Ca2(Al,Mn,Fe)3(SiO4)3(OH)=Ca2(Mn,Fe)Al2(SiO4)(Si2O7)O(OH) P 21/m 2/m |
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58.2.1a.12 Strontiopiemontite (Ca,Mn)(Sr,Ca)Mn(Al,Mn,Fe)2(SiO4)(Si2O7)O(OH) P 21/m 2/m |
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58.2.1a.13 Androsite-(La)! (Mn,Ca)(La,Ce,Ca,Nd)AlMnMn(SiO4)(Si2O7)O(OH) P 21/m 2/m |
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58.2.1a.14 Ferriallanite-(Ce)! CaCe(Fe,Fe,Al)3[SiO4][Si2O7]O(OH) P 21/m 2/m |
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58.2.1a.15 Tweddillite! CaSr(Mn,Fe)2Al[Si3O12](OH) P 21/m 2/m |
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58.2.1a.16 Gatelite-(Ce)! (Ca,Ce,La,Nd)4(Al,Mg,Fe)4[Si2O7][SiO4]3(O,F,OH)3 P 21/a 2/m |
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58.2.1a.17 Niigataite! CaSrAl3(Si2O7)(SiO4)O(OH) P 21/m 2/m |
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58.2.1a.18 Vastmanlandite-(Ce)! Ce3CaMg2Al2Si5O19(OH)2F P 21/m 2/m |
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58.2.1a.19 IMA2002-049! (Mn,Ca)(Ce,REE)AlMnMn(Si2O7)(SiO4)O(OH) P 21/m 2/m |
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58.2.1a.20 Dissakisite-(La)! (Ca,Fe,Th)(REE,Ca)(Al,Cr,Ti)2(Mg,Fe,Al)Si3O12(OH,F)withLa>Ce P 21/m 2/m |
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58.2.1a.22 IMA2004-015! (Mn,Ca)(REE)VAlMn(Si2O7)(SiO4)O(OH) P 21/m 2/m |
Strunz Class: |
VIII/C.23-30 VIII - Silicates |
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VIII/C - Sorosilicates, mixed structure with [SiO4]2- "inseln" and [Si2O7]6- groups |
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VIII/C.23 - Epidote group |
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VIII/C.23-10 Clinozoisite Ca2Al3(SiO4)3(OH)=Ca2AlAl2(SiO4)(Si2O7)O(OH) P 21/m 2/m |
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VIII/C.23-20 Epidote Ca2(Fe,Al)3(SiO4)3(OH)=Ca2(Fe,Al)Al2(SiO4)(Si2O7)O(OH) P 21/m 2/m |
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VIII/C.23-30 Piemontite Ca2(Al,Mn,Fe)3(SiO4)3(OH)=Ca2(Mn,Fe)Al2(SiO4)(Si2O7)O(OH) P 21/m 2/m |
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VIII/C.23-40 Strontiopiemontite (Ca,Mn)(Sr,Ca)Mn(Al,Mn,Fe)2(SiO4)(Si2O7)O(OH) P 21/m 2/m |
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VIII/C.23-43 Niigataite! CaSrAl3(Si2O7)(SiO4)O(OH) P 21/m 2/m |
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VIII/C.23-45 Tweddillite! CaSr(Mn,Fe)2Al[Si3O12](OH) P 21/m 2/m |
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VIII/C.23-50 Mukhinite Ca2Al2V(SiO4)3(OH) P 21/m 2/m |
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VIII/C.23-52 Androsite-(La)! (Mn,Ca)(La,Ce,Ca,Nd)AlMnMn(SiO4)(Si2O7)O(OH) P 21/m 2/m |
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VIII/C.23-55 Dollaseite-(Ce) CaCeMg2AlSi3O11(OH,F)2 P 21/m 2/m |
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VIII/C.23-58 Dissakisite-(Ce) Ca(Ce,REE)(Mg,Fe)(Al,Fe)2Si3O12(OH) P 21/m 2/m |
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VIII/C.23-60 Allanite-(Y) (Y,Ce,Ca)2(Al,Fe)3(SiO4)3(OH) P 21/m 2/m |
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VIII/C.23-65 Allanite-(La)! Ca(REE,Ca)Al2(Fe,Fe)(SiO4)(Si2O7)O(OH) P 21/m 2/m |
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VIII/C.23-80 Allanite-(Ce) (Ce,Ca,Y)2(Al,Fe)3(SiO4)3(OH) P 21/m 2/m |
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VIII/C.23-85a Ferriallanite-(Ce)! CaCe(Fe,Fe,Al)3[SiO4][Si2O7]O(OH) P 21/m 2/m |
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VIII/C.23-85 Khristovite-(Ce) (Ca,REE)(Ce,REE)(Mg,Fe,Cr,Ti,V,Al)MnAl(SiO4)(Si2O7)(OH)(F,O) P 21/m 2/m |
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VIII/C.23-87 Gatelite-(Ce)! (Ca,Ce,La,Nd)4(Al,Mg,Fe)4[Si2O7][SiO4]3(O,F,OH)3 P 21/a 2/m |
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VIII/C.23-90 Hancockite (Ca,Pb,Sr)2(Al,Fe)3(SiO4)(Si2O7)O(OH) P 21/m 2/m |
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VIII/C.23-100 Zoisite Ca2Al3(SiO4)3(OH)=Ca2AlAl2(SiO4)(Si2O7)O(OH) Pnmc 2/m 2/m 2/m |
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Other Piemontite Information
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References: |
NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65) |
See Also: |
Links to other databases for Piemontite :
1 -Am. Min. Crystal Structure Database
2 - Applied Mineralogy
3 -Athena
4 - Crocoite.com Mineral Locations
5 - EUROmin Project
6 - Franklin Minerals(Dunn)
7 -Google Images
8 -Google Scholar
9 -Handbook of Mineralogy (MinSocAm)
10 -Handbook of Mineralogy (UofA)
11 -MinDAT
12 -MinMax(Deutsch)
13 -MinMax(English)
14 -Mineralienatlas (Deutsch)
15 - Minerals in Thin Section-University of North Carolina
16 -QUT Mineral Atlas
17 - WWW-MINCRYST
18 -École des Mines de Paris
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Piemontite
Ca2(Al,Mn,Fe)3(SiO4)3(OH) = Ca2(Mn,Fe)Al2(SiO4)(Si2O7)O(OH)
Dana No: 58.2.1a.11 Strunz No: VIII/C.23-30
Locality:
Notes:
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