Jimthompsonite Mineral Data

Jimthompsonite Mineral Data +

General Jimthompsonite Information

Chemical Formula:

(Mg,Fe++)5Si6O16(OH)2

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

Empirical Formula:

Mg_3.75Fe²⁺_1.25Si₆O₁₆(OH)₂

IMA Status:

Approved IMA 1978

Locality:

Link to MinDat.org Location Data.

Synonym:

ICSD 100657

PDF 31-638

Jimthompsonite Image

Images:

Click Here for Larger Jimthompsonite Image

Jimthompsonite Clinojimthompsonite

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

Axial Ratios:

a:b:c =0.684:1:0.1945

Cell Dimensions:

a = 18.626, b = 27.23, c = 5.297, Z = 8; V = 2,686.56 Den(Calc)= 3.06

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: P bca

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 8.812(1), 13.6(0.57), 3.092(0.53),

Crystal Structure:

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Veblen D R , Burnham C W , American Mineralogist , 63 (1978) p.1053-1073, New biopyriboles from Chester, Vermont: II. The crystal chemistry of, jimthompsonite, clinojimthompsonite, and chesterite, and the amphibole-mica, reaction

Physical Properties of Jimthompsonite

Cleavage:

[210] Perfect

Color:

Colorless, Pink brown.

Density:

3.03

Diaphaniety:

Transparent

Hardness:

2-2.5 - Gypsum-Finger Nail

Luster:

Silky - Pearly

Streak:

white

Optical Properties of Jimthompsonite

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

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

Electron Density:

r_electron=3.01 gm/cc
note: r_{Jimthompsonite}=3.03 gm/cc.

Fermion Index

Fermion Index = 0.03002
Boson Index = 0.96998

Photoelectric:

PE_{Jimthompsonite}= 4.68 barns/electron
U=PE_{Jimthompsonite} x r_electron= 14.09 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Jimthompsonite is Not Radioactive

Jimthompsonite Classification

Dana Class:

67.1.1.1 (67)Inosilicate Unbranched Chains with W>2

(67.1)with W=3

(67.1.1)Jimthompsonite group

67.1.1.1 Jimthompsonite (Mg,Fe)5Si6O16(OH)2 P bca 2/m 2/m 2/m

67.1.1.2 Clinojimthompsonite (Mg,Fe)5Si6O16(OH)2 C 2/c 2/m

Strunz Class:

VIII/F.13-30 VIII - Silicates

VIII/F - Inosilicates (chain and band) double chains [Si4O11]6-, Orthorhombic Amphiboles

VIII/F.13 - Amphibole group, Chesterite - Jimthomsonite series

VIII/F.13-10 Chesterite (Mg,Fe)17Si20O54(OH)6 A21ma mm2

VIII/F.13-20 Clinojimthompsonite (Mg,Fe)5Si6O16(OH)2 C 2/c 2/m

VIII/F.13-30 Jimthompsonite (Mg,Fe)5Si6O16(OH)2 P bca 2/m 2/m 2/m

Other Jimthompsonite Information

References:

PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Jimthompsonite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (MinSocAm) 7 -Handbook of Mineralogy (UofA) 8 -MinDAT 9 -MinMax(Deutsch) 10 -MinMax(English) 11 -Mineralienatlas (Deutsch) 12 -QUT Mineral Atlas 13 - WWW-MINCRYST 14 -École des Mines de Paris

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Jimthompsonite

(Mg,Fe++)5Si6O16(OH)2
Dana No: 67.1.1.1 Strunz No: VIII/F.13-30
Locality:

Notes: