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Piemontite Mineral Data

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General Piemontite Information

Help on Chemical  Formula: Chemical Formula: Ca2(Al,Mn,Fe)3(SiO4)3(OH) = Ca2(Mn,Fe)Al2(SiO4)(Si2O7)O(OH)
Help on Composition: Composition: Molecular Weight = 488.18 gm
   Calcium    16.42 %  Ca   22.97 % CaO
   Manganese  10.13 %  Mn   13.08 % MnO
   Aluminum    9.95 %  Al   18.80 % Al2O3
   Iron        3.43 %  Fe    4.42 % FeO
   Silicon    17.26 %  Si   36.92 % SiO2
   Hydrogen    0.21 %  H     1.85 % H2O
   Oxygen     42.61 %  O
             ______        ______ 
             100.00 %       98.03 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Ca2Al1.8Mn2+0.9Fe2+0.3(SiO4)3(OH)
Help on Environment: Environment: Contact metamorphic rocks.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1853 - Dana number changed from 58.2.1a.11
Help on Locality: Locality: Piedmont, Italy. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named after its locality.
Help on Name Pronunciation: Name Pronunciation: Piemontite + Pronunciation Say PIEMONTITE
Help on Synonym: Synonym: Piedmontite
 

Piemontite Image

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  Piemontite

Comments: Red, acicular crystalline aggregates of piemontite.
Location: N'Chwaning mine, Kuruman, Nothern Cape, South Africa. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Piemontite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =1.5609:1:1.7917
Help on Cell Dimensions: Cell Dimensions: a = 8.843, b = 5.665, c = 10.15, Z = 2; beta = 115.4° V = 459.32 Den(Calc)= 3.53
Help on Crystal System: Crystal System: Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 21/m
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.903(1), 2.598(0.5), 4(0.5),
 

Physical Properties of Piemontite

Help on Cleavage: Cleavage: {001} Good, {100} Distinct
Help on Color: Color: Yellow, Carmine red, Red, Reddish brown, Reddish black.
Help on Density: Density: 3.4
Help on Diaphaneity: Diaphaneity: Translucent
Help on Fracture: Fracture: Splintery - Thin, elongated fractures produced by intersecting good cleavages or partings (e.g. hornblende).
Help on Habit: Habit: Blocky - Crystal shape tends to be equant (e.g. feldspars).
Help on Habit: Habit: Massive - Granular - Common texture observed in granite and other igneous rock.
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Help on Hardness: Hardness: 6-7 - Orthoclase-Quartz
Help on Luminescence: Luminescence: Non-fluorescent.
Help on Luster: Luster: Vitreous (Glassy)
Help on Magnetism: Magnetism: Nonmagnetic
Help on Streak: Streak: red
 

Optical Properties of Piemontite

Help on Gladstone-Dale: 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
Ncalc = 1.69 - 1.72
Help on Optical Data: 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.
Help on Pleochroism (x): Pleochroism (x): pale yellow, yellow, lemon yellow, orange, or red.
Help on Pleochroism (y): Pleochroism (y): pale purple, amethyst violet, violet, rose, or deep red.
 

Calculated Properties of Piemontite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.48 gm/cc
note: Specific Gravity of Piemontite =3.53 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0092141919
Boson Index = 0.9907858081
Help on Photoelectric: Photoelectric: PEPiemontite = 6.55 barns/electron
U=PEPiemontite x rElectron Density= 22.82 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Piemontite is Not Radioactive
 

Piemontite Classification

Help on  Dana Class: Dana Class: 58.02.01a.05 (58)Sorosilicate Insular, Mixed, Single, and Larger Tetrahedral Groups
  (58.02)with cations in [6] and higher coordination; single and double groups (n=1,2)
  (58.02.01a)Epidote group (Clinozoisite subgroup)
 
58.02.01a.01 Clinozoisite! Ca2Al3(SiO4)3(OH)=Ca2AlAl2(SiO4)(Si2O7)O(OH) P 21/m 2/m
 
58.02.01a.02 Epidote! Ca2(Fe,Al)3(SiO4)3(OH)=Ca2(Fe,Al)Al2(SiO4)(Si2O7)O(OH) P 21/m 2/m
 
58.02.01a.03 Epidote-(Pb)! (Ca,Pb,Sr)2(Al,Fe)3(SiO4)(Si2O7)O(OH) P 21/m 2/m
 
58.02.01a.04 Mukhinite Ca2Al2V(SiO4)3(OH) P 21/m 2/m
 
58.02.01a.05 Piemontite Ca2(Al,Mn,Fe)3(SiO4)3(OH)=Ca2(Mn,Fe)Al2(SiO4)(Si2O7)O(OH) P 21/m 2/m
 
58.02.01a.06 Piemontite-(Sr)! (Ca,Mn)(Sr,Ca)Mn(Al,Mn,Fe)2(SiO4)(Si2O7)O(OH) P 21/m 2/m
 
58.02.01a.07 Manganipiemontite-(Sr)! CaSr(Mn,Fe)2Al[Si3O12](OH) P 21/m 2/m
 
58.02.01a.08 Gatelite-(Ce)! (Ca,Ce,La,Nd)4(Al,Mg,Fe)4[Si2O7][SiO4]3(O,F,OH)3 P 21/a 2/m
 
58.02.01a.09 Clinozoisite-(Sr)! CaSrAl3(Si2O7)(SiO4)O(OH) P 21/m 2/m
 
58.02.01a.10 Uedaite-(Ce)! MnCeAl2Fe(Si2O7)(SiO4)O(OH) P 21/m 2/m
 
58.02.01a.11 Epidote-(Sr)! CaSrAl2Fe(Si2O7)(SiO4)O(OH) P 21/m 2/m
Help on  Strunz Class: Strunz Class: 09.BG.05a 09 - SILICATES (Germanates)
  09.B - Sorosilicates
  09.BG -Sorosilicates with mixed SiO4 and Si2O7 groups;
 
09.BG.05a Clinozoisite Ca2Al3(SiO4)3(OH)=Ca2AlAl2(SiO4)(Si2O7)O(OH) P 21/m 2/m
 
09.BG.05a Epidote Ca2(Fe,Al)3(SiO4)3(OH)=Ca2(Fe,Al)Al2(SiO4)(Si2O7)O(OH) P 21/m 2/m
 
09.BG.05a Epidote-(Pb) (Ca,Pb,Sr)2(Al,Fe)3(SiO4)(Si2O7)O(OH) P 21/m 2/m
 
09.BG.05a Mukhinite Ca2Al2V(SiO4)3(OH) P 21/m 2/m
 
09.BG.05a Piemontite Ca2(Al,Mn,Fe)3(SiO4)3(OH)=Ca2(Mn,Fe)Al2(SiO4)(Si2O7)O(OH) P 21/m 2/m
 
09.BG.05a Piemontite-(Sr)! (Ca,Mn)(Sr,Ca)Mn(Al,Mn,Fe)2(SiO4)(Si2O7)O(OH) P 21/m 2/m
 
09.BG.05a Manganipiemontite-(Sr)! CaSr(Mn,Fe)2Al[Si3O12](OH) P 21/m 2/m
 
09.BG.05a Clinozoisite-(Sr)! CaSrAl3(Si2O7)(SiO4)O(OH) P 21/m 2/m
 
09.BG.05a Epidote-(Sr)! CaSrAl2Fe(Si2O7)(SiO4)O(OH) P 21/m 2/m
 

Other Piemontite Information

Help on See Also: See Also: Links to other databases for Piemontite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - Franklin Minerals(Dunn)
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Minerals in Thin Section-University of North Carolina
14 - Online Mineral Museum
15 - QUT Mineral Atlas
16 - Ruff.Info
17 - WWW-MINCRYST

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Piemontite

Ca2(Al,Mn,Fe)3(SiO4)3(OH) = Ca2(Mn,Fe)Al2(SiO4)(Si2O7)O(OH)
Dana No: 58.02.01a.05 Strunz No: 09.BG.05a
Locality:

 

Notes:

 

 


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