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Talmessite Mineral Data

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General Talmessite Information

Help on Chemical  Formula: Chemical Formula: Ca2Mg(AsO4)2•2(H2O)
Help on Composition: Composition: Molecular Weight = 418.33 gm
   Calcium    19.16 %  Ca   26.81 % CaO
   Magnesium   5.81 %  Mg    9.63 % MgO
   Arsenic    35.82 %  As   54.94 % As2O5
   Hydrogen    0.96 %  H     8.61 % H2O
   Oxygen     38.25 %  O
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Ca2Mg(AsO4)2•2(H2O)
Help on Environment: Environment: Secondary species formed typically in the oxidized zone of some hydrothermal mineral deposits, an alteration product of realgar, orpiment, or Cu-Ni arsenides.
Help on IMA Status: IMA Status: Approved IMA 1960
Help on Locality: Locality: Talmessi mine, 35 km west of Anarak, Iran. In the Arhbar (Aghbar) and A�it Ahmane mines, Bou Azzer district, Morocco. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for the locality.
Help on Name Pronunciation: Name Pronunciation: Talmessite + Pronunciation Say TALMESSITE
Help on Synonym: Synonym: ICSD 200008
  PDF 38-451
 

Talmessite Image

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  Talmessite

Comments: Pale green, crystalline aggregates of talmessite on reddish, hematite-stained calcite.
Location: Ourlil, Bou Azzer, Anti Atlas Mts., Morocco. Scale: Crystal size 4 mm.
© John Veevaert

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  Talmessite

Comments: Translucent nearly colorless talmessite microcrystals.
Location: Old Gold Hill Mine, Tooele County, Utah, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

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  Talmessite

Comments: Vivid pink-colored talmessite crystalline aggregates scattered on matrix.
Location: Bou Azzer, Morocco. Scale: Picture size 2 cm.
© Sandro Maggia/Minernet.it

Talmessite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.7659:1:0.723
Help on Cell Dimensions: Cell Dimensions: a = 5.89, b = 7.69, c = 5.56, Z = 1; alpha = 112.633°, beta = 70.817°, gamma = 119.417° V = 191.23 Den(Calc)= 3.63
Help on Crystal System: Crystal System: Triclinic - Pinacoidal H-M Symbol ( 1) Space Group: P1
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.77(1), 3.07(1), 3.21(0.8),
 

Physical Properties of Talmessite

Help on Color: Color: Colorless, White, Light green.
Help on Density: Density: 3.2 - 3.5, Average = 3.35
Help on Diaphaneity: Diaphaneity: Transparent to Translucent
Help on Hardness: Hardness: 5 - Apatite
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white
 

Optical Properties of Talmessite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.055 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.015 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1968,KPDmeas= 0.2045,KC= 0.1939
Ncalc = 1.62 - 1.68
Help on Optical Data: Optical Data: Biaxial (-), a=1.672, b=1.685, g=1.698, bire=0.0260, 2V(Calc)=88, 2V(Meas)=90.
 

Calculated Properties of Talmessite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.36 gm/cc
note: Specific Gravity of Talmessite =3.48 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0062537058
Boson Index = 0.9937462942
Help on Photoelectric: Photoelectric: PETalmessite = 26.60 barns/electron
U=PETalmessite x rElectron Density= 89.40 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Talmessite is Not Radioactive
 

Talmessite Classification

Help on  Dana Class: Dana Class: 40.02.02.05 (40)Hydrated Phosphates, etc
  (40.02)where A++ (B++)2 (XO4) � x(H2O)
  (40.02.02)Fairfieldite Subgroup (Triclinic: P-1�)
 
40.02.02.01 Fairfieldite Ca2(Mn,Fe)(PO4)2•2(H2O) P1 1
 
40.02.02.02 Messelite Ca2(Fe,Mn)(PO4)2•2(H2O) P1 1
 
40.02.02.03 Collinsite Ca2(Mg,Fe)(PO4)2•2(H2O) P1 1
 
40.02.02.04 Cassidyite Ca2(Ni,Mg)(PO4)2•2(H2O) P1 1
 
40.02.02.05 Talmessite Ca2Mg(AsO4)2•2(H2O) P1 1
 
40.02.02.06 Gaitite Ca2Zn(AsO4)2•2(H2O) P1 1
 
40.02.02.07 Roselite-beta Ca2(Co,Mg)(AsO4)2•2(H2O) P 1 or P1 Tri
 
40.02.02.08 Parabrandtite Ca2Mn(AsO4)•2(H2O) P1,P 1 Tri
 
40.02.02.09 Hillite! Ca2(Zn,Mg)[PO4]2•2(H2O) P1 1
 
40.02.02.10 Nickeltalmessite! Ca2Ni(AsO4)2•2H2O P 1
Help on  Strunz Class: Strunz Class: 08.CG.05 08 - PHOSPHATES, ARSENATES, VANADATES
  08.C - Phosphates without Additional Anions, with H2O
  08.CG -With large and medium-sized cations, RO4:H2O = 1:1
 
08.CG.05 Collinsite Ca2(Mg,Fe)(PO4)2•2(H2O) P1 1
 
08.CG.05 Gaitite Ca2Zn(AsO4)2•2(H2O) P1 1
 
08.CG.05 Cassidyite Ca2(Ni,Mg)(PO4)2•2(H2O) P1 1
 
08.CG.05 Fairfieldite Ca2(Mn,Fe)(PO4)2•2(H2O) P1 1
 
08.CG.05 Messelite Ca2(Fe,Mn)(PO4)2•2(H2O) P1 1
 
08.CG.05 Parabrandtite Ca2Mn(AsO4)•2(H2O) P1,P 1 Tri
 
08.CG.05 Uranophane-beta Ca[(UO2)SiO3(OH)]2•(H2O) P 21/a 2/m
 
08.CG.05 Talmessite Ca2Mg(AsO4)2•2(H2O) P1 1
 
08.CG.05 Hillite! Ca2(Zn,Mg)[PO4]2•2(H2O) P1 1
 

Other Talmessite Information

Help on References: References: NAME( AntBidBlaNic4) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)
Help on See Also: See Also: Links to other databases for Talmessite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST

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Print or Cut-and-Paste your Talmessite Specimen Label here :

Talmessite

Ca2Mg(AsO4)2•2(H2O)
Dana No: 40.02.02.05 Strunz No: 08.CG.05
Locality:

 

Notes:

 

 
   
 


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