Piemontite-(Sr) Mineral Data

General Piemontite-(Sr) Information

Chemical Formula:

(Ca,Mn++)(Sr,Ca)Mn+++(Al,Mn+++,Fe+++)2(SiO4)(Si2O7)O(OH)

Composition:

Molecular Weight = 524.43 gm

Strontium 11.70 % Sr 13.83 % SrO

Calcium 8.41 % Ca 11.76 % CaO

Manganese 11.52 % Mn 2.71 % MnO / 13.55 % Mn₂O₃

Aluminum 9.26 % Al 17.50 % Al₂O₃

Iron 3.19 % Fe 4.57 % Fe₂O₃

Silicon 16.07 % Si 34.37 % SiO₂

Hydrogen 0.19 % H 1.72 % H₂O

Oxygen 39.66 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca_0.8Mn²⁺_0.2Sr_0.7Ca_0.3Al_1.8Mn³⁺_0.9Fe³⁺_0.3Si₃O₁₂(OH)

Environment:

As veinlets in a low-temperature metamorphosed manganese ore deposit.

IMA Status:

Approved IMA 1990 - Dana # changed from 58.2.1a.12

Locality:

From the Molinello and Cassagna manganese mines, near Chiavari, Val Graveglia, Liguria, Italy. Link to MinDat.org Location Data.

Name Origin:

From its strontium content and similarity to piemontite.

Name Pronunciation:

Piemontite-(Sr) + Pronunciation

Synonym:

IMA1989-031

Strontiopiemontite - Renamed to Piemontite-(Sr) - Recommended nomenclature of epidote-group minerals, Eur. J. Mineral. 2006, 18, 551-567.

Piemontite-(Sr) Image

Images:

Piemontite-(Sr)

Comments: Carmine red crystals of piemontite-(Sr) found on quartz.
Location: Graveglia, Piemont, Italy. Scale: See Image.
© Rruff Database

Piemontite-(Sr) Crystallography

Axial Ratios:

a:b:c =1.5596:1:1.7935

Cell Dimensions:

a = 8.862, b = 5.682, c = 10.191, Z = 2; beta = 114.7° V = 466.21 Den(Calc)= 3.74

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/I_o): 2.916(1), 2.936(0.5), 3.493(0.5),

Physical Properties of Piemontite-(Sr)

Cleavage:

{001} Perfect

Color:

Dark red.

Density:

3.65 - 3.73, Average = 3.69

Diaphaneity:

Transparent

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

6 - Orthoclase

Luster:

Vitreous (Glassy)

Streak:

purple brown

Optical Properties of Piemontite-(Sr)

Gladstone-Dale:

CI meas= 0.055 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.068 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.204,KPDmeas= 0.2068,KC= 0.2188
Ncalc = 1.8 - 1.82

Optical Data:

Biaxial (+), b=1.763

Pleochroism (x):

orange yellow.

Pleochroism (y):

violet.

Pleochroism (z):

reddish violet.

Calculated Properties of Piemontite-(Sr)

Electron Density:

Bulk Density (Electron Density)=3.58 gm/cc
note: Specific Gravity of Piemontite-(Sr) =3.69 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_{Piemontite-(Sr)}= 18.61 barns/electron
U=PE_{Piemontite-(Sr)} x rElectron Density= 66.58 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Piemontite-(Sr) is Not Radioactive

Piemontite-(Sr) Classification

Dana Class:

58.02.01a.06 (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

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-(Sr) Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Am.Min.,Vol.76,p668,1991) OPTIC PROP.(AntBidBlaNic2)

See Also:

Links to other databases for Piemontite-(Sr) :
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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Piemontite-(Sr)

(Ca,Mn++)(Sr,Ca)Mn+++(Al,Mn+++,Fe+++)2(SiO4)(Si2O7)O(OH)
Dana No: 58.02.01a.06 Strunz No: 09.BG.05a
Locality:

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