Mineralogy Database

Jimthompsonite Mineral Data

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General Jimthompsonite Information

Help on Chemical  Formula: Chemical Formula: (Mg,Fe++)5Si6O16(OH)2
Help on Composition: Composition: Molecular Weight = 619.47 gm
   Magnesium  14.71 %  Mg   24.40 % MgO
   Iron       11.27 %  Fe   14.50 % FeO
   Silicon    27.20 %  Si   58.20 % SiO2
   Hydrogen    0.33 %  H     2.91 % H2O
   Oxygen     46.49 %  O
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Mg3.75Fe2+1.25Si6O16(OH)2
Help on Environment: Environment: In the black wallrock between chlorite and actinolite zones of a metamorphosed ultramafic body.
Help on IMA Status: IMA Status: Approved IMA 1978
Help on Locality: Locality: In the Carleton talc quarry, near Chester, Windsor Co., Vermont, USA. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for James Burleigh Thompson, Jr. (1921- ), eminent petrologist of Harvard University, Cambridge, Massachusetts, USA.
Help on Name Pronunciation: Name Pronunciation: Jimthompsonite + Pronunciation Say JIMTHOMPSONITE
Help on Synonym: Synonym: ICSD 100657
  PDF 31-638

Jimthompsonite Image

Click Here for Larger   Image in a New Browser Window Images:
Click Here for Larger   Image

  Clinojimthompsonite   Jimthompsonite

Comments: Pale green to white glassy crystalline fibrous clinojimthompsonite intergrown with jimthompsonite.
Location: Chester, Windsor County, Vermont, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Jimthompsonite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.684:1:0.1945
Help on Cell Dimensions: Cell Dimensions: a = 18.626, b = 27.23, c = 5.297, Z = 8; V = 2,686.56 Den(Calc)= 3.06
Help on Crystal System: Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: P bca
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 8.812(1), 13.6(0.57), 3.092(0.53),

Physical Properties of Jimthompsonite

Help on Cleavage: Cleavage: {210} Perfect
Help on Color: Color: Colorless, Pink brown.
Help on Density: Density: 3.03
Help on Diaphaneity: Diaphaneity: Transparent
Help on Hardness: Hardness: 2-2.5 - Gypsum-Finger Nail
Help on Luster: Luster: Silky - Pearly
Help on Streak: Streak: white

Optical Properties of Jimthompsonite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.009 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.019 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2031,KPDmeas= 0.2051,KC= 0.207
Ncalc = 1.63
Help on Optical Data: Optical Data: Biaxial (-), a=1.605, b=1.626, g=1.633, bire=0.0280, 2V(Calc)=58, 2V(Meas)=62.

Calculated Properties of Jimthompsonite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.01 gm/cc
note: Specific Gravity of Jimthompsonite =3.03 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.03
Boson Index = 0.97
Help on Photoelectric: Photoelectric: PEJimthompsonite = 4.68 barns/electron
U=PEJimthompsonite x rElectron Density= 14.09 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Jimthompsonite is Not Radioactive

Jimthompsonite Classification

Help on  Dana Class: Dana Class: (67)Inosilicate Unbranched Chains with W>2
  (67.01)with W=3
  (67.01.01)Jimthompsonite group Jimthompsonite (Mg,Fe)5Si6O16(OH)2 P bca 2/m 2/m 2/m Clinojimthompsonite (Mg,Fe)5Si6O16(OH)2 C 2/c 2/m
Help on  Strunz Class: Strunz Class: 09.DF.05 09 - SILICATES (Germanates)
  09.D - Inosilicates* Structural terminology according to Liebau (1985)
  09.DF -Inosilicates with 2-periodic multiple chains
09.DF.05 Chesterite (Mg,Fe)17Si20O54(OH)6 A21ma mm2
09.DF.05 Clinojimthompsonite (Mg,Fe)5Si6O16(OH)2 C 2/c 2/m
09.DF.05 Jimthompsonite (Mg,Fe)5Si6O16(OH)2 P bca 2/m 2/m 2/m

Other Jimthompsonite Information

Help on References: References: NAME( AntBidBlaNic2) 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 Jimthompsonite :
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

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Dana No: Strunz No: 09.DF.05





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