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Jimthompsonite

A valid IMA mineral species

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Jimthompsonite

Carlton Quarry, Chester, Windsor County, Vermont, USA

Jimthompsonite, etc.

Chester, Windsor County, Vermont, USA

Jimthompsonite, etc.

Carlton Quarry, Chester, Windsor County, Vermont, USA

Jimthompsonite

Carlton Quarry, Chester, Windsor County, Vermont, USA

Jimthompsonite, etc.

Chester, Windsor County, Vermont, USA

Jimthompsonite, etc.

Carlton Quarry, Chester, Windsor County, Vermont, USA

Jimthompsonite

Carlton Quarry, Chester, Windsor County, Vermont, USA

Jimthompsonite, etc.

Chester, Windsor County, Vermont, USA

Hide all sections | Show all sections

About JimthompsoniteHide

James B. Thompson, Jr.

Formula:

(Mg,Fe)₅Si₆O₁₆(OH)₂

Colour:

Colorless to very light pinkish brown

Lustre:

Vitreous, Sub-Vitreous

Hardness:

6 - 7

Specific Gravity:

3.05 (Calculated)

Crystal System:

Orthorhombic

Name:

Named by David R. Veblen and Charles W. Burnham in 1978 in honor of James (Jim) B. Thompson, jr., [November 20, 1921 Calais, Maine, USA - November 15, 2011, Calais, Maine, USA], mineralogist and petrologist, late professor/emeritus at Harvard University, USA.

Type Locality:

ⓘ Carlton Quarry, Chester, Windsor County, Vermont, USA

Jimthompsonite occurs as ultra-microscopic intergrowths within other host minerals, generally amphiboles such as anthophyllite or cummingtonite-series minerals. Jimthompsonite is generally not visible to the naked eye, but instead is observable optically or by transmission electron microscopy.

Unique IdentifiersHide

Mindat ID:

2096

Long-form identifier:

mindat:1:1:2096:7

IMA Classification of JimthompsoniteHide

IMA status:

Approved

IMA Formula:

Mg₅Si₆O₁₆(OH)₂

Approval year:

1977

First published:

1978

Classification of JimthompsoniteHide

Strunz-mindat (2026):

9.DF.05

9 : SILICATES (Germanates)
D : Inosilicates
F : Inosilicates with 2-periodic multiple chains

Dana 8th ed.:

67.1.1.1

67 : INOSILICATES Unbranched Chains with W > 2
1 : Unbranched Chains with W>2 with W=3

Hey's CIM Ref.:

14.21.11

14 : Silicates not Containing Aluminum
21 : Silicates of Fe and Mg

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.

Symbol	Source	Reference for Standard
Jim	IMA–CNMNC	Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43
Jim	Whitney & Evans (2010)	Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185–187 doi:10.2138/am.2010.3371

Physical Properties of JimthompsoniteHide

Lustre:

Vitreous, Sub-Vitreous

Transparency:

Transparent

Colour:

Colorless to very light pinkish brown

Streak:

Colorless

Hardness:

6 - 7 on Mohs scale

Hardness Data:

Estimated

Comment:

Undetermined; presumably similar to amphibole.

Tenacity:

Brittle

Cleavage:

Perfect
Perfect on {210}, intersecting at 38° and 142°.

Parting:

Breakage on {100} and {010} may be partings.

Fracture:

Splintery

Density:

3.05 g/cm³ (Calculated)

Optical Data of JimthompsoniteHide

Type:

Biaxial (-)

RI values:

n_α = 1.605 n_β = 1.626 n_γ = 1.633

2V:

Measured: 62° , Calculated: 58°

Birefringence:

0.028

Max. Birefringence:

δ = 0.028
Based on recorded range of RI values above.

Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.

Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.

Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.

Thickness: 30 µm Order divisions

Rotation:

Surface Relief:

Moderate

Dispersion:

r > v weak

Optical Extinction:

Parallel. XYZ = abc.

Pleochroism:

Non-pleochroic

Chemistry of JimthompsoniteHide

Mindat Formula:

(Mg,Fe)₅Si₆O₁₆(OH)₂

Element Weights:

Element	% weight
O	49.650 %
Si	29.052 %
Mg	20.951 %
H	0.348 %

Calculated from ideal end-member formula.

Elements listed:

Fe, H, Mg, O, Si - search for minerals with similar chemistry

Common Impurities:

Al,Mn,Ca,Na,H₂O

Crystallography of JimthompsoniteHide

Crystal System:

Orthorhombic

Class (H-M):

mmm(2/m2/m2/m) - Dipyramidal

Space Group:

Pbca

Setting:

Pbca

Cell Parameters:

a = 18.626 Å, b = 27.23 Å, c = 5.297 Å

Ratio:

a:b:c = 0.684 : 1 : 0.195

Unit Cell V:

2,686.56 Å³ (Calculated from Unit Cell)

Morphology:

Fibrous intergrowths in host crystals to 5 cm.

Crystal StructureHide

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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4

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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure

ID	Species	Reference	Link	Year	Locality	Pressure (GPa)	Temp (K)
0000687	Jimthompsonite	Veblen D R, Burnham C W (1978) New biopyriboles from Chester, Vermont: II. The crystal chemistry of jimthompsonite, clinojimthompsonite, and chesterite, and the amphibole-mica reaction American Mineralogist 63 1053-1073		1978		0	293

CIF Raw Data - click here to close

data_global
_chemical_name_mineral 'Jimthompsonite'
loop_
_publ_author_name
'Veblen D R'
'Burnham C W'
_journal_name_full 'American Mineralogist'
_journal_volume 63 
_journal_year 1978
_journal_page_first 1053
_journal_page_last 1073
_publ_section_title
;
 New biopyriboles from Chester, Vermont: II. The crystal chemistry of
 jimthompsonite, clinojimthompsonite, and chesterite, and the amphibole-mica
 reaction
;
_database_code_amcsd 0000687
_chemical_formula_sum '(Mg3.892 Fe1.108) Si6 (O18 H2)'
_cell_length_a 18.626
_cell_length_b 27.230
_cell_length_c 5.297
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 2686.564
_exptl_crystal_density_diffrn      3.041
_symmetry_space_group_name_H-M 'P b c a'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x,1/2-y,1/2+z'
  '-x,1/2+y,1/2-z'
  '1/2-x,1/2+y,z'
  '1/2+x,1/2-y,-z'
  '1/2+x,y,1/2-z'
  '1/2-x,-y,1/2+z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_U_iso_or_equiv
Mg1   0.12565   0.27883   0.89663   0.94000   0.00545
Fe1   0.12565   0.27883   0.89663   0.06000   0.00545
Mg2   0.12535   0.33533   0.39566   0.84400   0.00735
Fe2   0.12535   0.33533   0.39566   0.15600   0.00735
Mg3   0.12506   0.39257   0.89577   0.92200   0.00532
Fe3   0.12506   0.39257   0.89577   0.07800   0.00532
Mg4   0.12485   0.45165   0.39642   0.98900   0.00443
Fe4   0.12485   0.45165   0.39642   0.01100   0.00443
Fe5   0.12369   0.50609   0.89507   0.80300   0.00697
Mg5   0.12369   0.50690   0.89507   0.19700   0.00697
Si1a   0.27111   0.27787   0.55967   1.00000   0.00380
Si2a   0.26964   0.39005   0.56980   1.00000   0.00507
Si3a   0.27242   0.44700   0.06669   1.00000   0.00532
Si1b   0.48025   0.27769   0.26700   1.00000   0.00418
Si2b   0.48078   0.38929   0.27278   1.00000   0.00545
Si3b   0.47579   0.44553   0.77466   1.00000   0.00595
O-Ha   0.18329   0.33519   0.06241   1.00000   0.00621
O-Hb   0.56861   0.33513   0.76931   1.00000   0.00633
O1a   0.30061   0.24981   0.31159   1.00000   0.00823
O2a   0.18399   0.27777   0.56140   1.00000   0.00507
O3a   0.29949   0.33407   0.55638   1.00000   0.00861
O4a   0.18325   0.39170   0.56291   1.00000   0.00633
O5a   0.29980   0.41491   0.82585   1.00000   0.00925
O6a   0.30187   0.42028   0.33148   1.00000   0.00874
O7a   0.18560   0.44852   0.06801   1.00000   0.00697
O8a   0.31330   0.49841   0.08080   1.00000   0.00773
O1b   0.45141   0.24443   0.03443   1.00000   0.00684
O2b   0.56718   0.27792   0.26828   1.00000   0.00519
O3b   0.45168   0.33338   0.23045   1.00000   0.00823
O4b   0.56725   0.39207   0.27127   1.00000   0.00760
O5b   0.44881   0.42441   0.05168   1.00000   0.00747
O6b   0.45138   0.40886   0.54386   1.00000   0.00963
O7b   0.56296   0.44849   0.77718   1.00000   0.00798
O8b   0.43394   0.49561   0.71391   1.00000   0.00785

X-Ray Powder DiffractionHide

Powder Diffraction Data:

d-spacing	Intensity
13.6 Å	(60)
8.81 Å	(100)
3.81 Å	(30)
3.25 Å	(40)
3.09 Å	(50)
2.74 Å	(30)
2.60 Å	(40)
2.55 Å	(30)

Comments:

ICDD 31-638 (calculated)

Geological EnvironmentHide

Paragenetic Mode(s):

Paragenetic Mode	Earliest Age (Ga)
Stage 2: Planetesimal differentiation and alteration	4.566-4.550
6 : Secondary asteroid phases	4.566-4.560
Stage 5: Initiation of plate tectonics	<3.5-2.5
40 : Regional metamorphism (greenschist, amphibolite, granulite facies)

Type Occurrence of JimthompsoniteHide

Type Locality:

ⓘ Carlton Quarry, Chester, Windsor County, Vermont, USA

General Appearance of Type Material:

Occurs as fibrous crystals or microscopic intergrowths parallel to (010) in anthophyllite and cummingtonite.

Place of Conservation of Type Material:

Royal Ontario Museum, Toronto, Canada, M36083.
Harvard University, Cambridge, Massachusetts, USA.
National Museum of Natural History, Washington, D.C., USA, 145689.

Geological Setting of Type Material:

Found in the blackwall zone of a metamorphosed ultramafic body.

Associated Minerals at Type Locality:

Actinolite	Anthophyllite	Chesterite	Clinochlore	Cummingtonite
Magnetite	Talc

Synonyms of JimthompsoniteHide

IMA1977-011

Other Language Names for JimthompsoniteHide

Dutch:Jimthompsoniet

German:Jimthompsonit

Russian:Джимтомпсонит

Simplified Chinese:镁川石

Spanish:Jimthompsonita

Common AssociatesHide

Associations Based on Photo Data:

13 photos of Jimthompsonite associated with Clinojimthompsonite	(Mg,Fe)₅Si₆O₁₆(OH)₂
12 photos of Jimthompsonite associated with Chesterite	(Mg,Fe)₁₇Si₂₀O₅₄(OH)₆
11 photos of Jimthompsonite associated with Anthophyllite	◻Mg₂Mg₅(Si₈O₂₂)(OH)₂
10 photos of Jimthompsonite associated with Talc	Mg₃Si₄O₁₀(OH)₂
10 photos of Jimthompsonite associated with Magnetite	Fe²⁺Fe³⁺₂O₄
3 photos of Jimthompsonite associated with Pyrite	FeS₂

Related Minerals - Strunz-mindat Grouping Hide

9.DF.	Bohseite	Ca₄Be_3+xAl_1-xSi₉O_25-x(OH)_3+x	Orth. mmm(2/m2/m2/m) : Cmcm
9.DF.05	Clinojimthompsonite	(Mg,Fe)₅Si₆O₁₆(OH)₂	Mon. 2/m : B2/b
9.DF.05	Chesterite	(Mg,Fe)₁₇Si₂₀O₅₄(OH)₆	Orth. mm2
9.DF.15	Ershovite	Na₄K₃(Fe,Mn,Ti)₂Si₈O₂₂(OH)₄ · 4H₂O	Tric. 1 : P1
9.DF.15	Paraershovite	Na₃K₃Fe³⁺₂Si₈O₂₀(OH)₄ · 4H₂O	Tric. 1 : P1
9.DF.20	Tvedalite	(Ca,Mn)₄Be₃Si₆O₁₇(OH)₄ · 3H₂O	Orth.
9.DF.25	Bavenite	Ca₄Be₂Al₂Si₉O₂₆(OH)₂	Orth. mm2
9.DF.30	Bigcreekite	BaSi₂O₅ · 4H₂O	Orth. mmm(2/m2/m2/m) : Pnma

Fluorescence of JimthompsoniteHide

In UV light:

Not fluorescent

Other InformationHide

Health Risks:

No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

Internet Links for JimthompsoniteHide

mindat.org URL:

https://www.mindat.org/min-2096.html
Please feel free to link to this page.

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External Links:

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Look for Jimthompsonite on Mineralien Atlas

Raman and XRD data at RRUFF project

References and PDF downloads at RRUFF project

American Mineralogist Crystal Structure Database

Handbook of Mineralogy page PDF

Mineral Dealers:

Buy from D. Joyce minerals

References for JimthompsoniteHide

Reference List:

Veblen, David R., Burnham, Charles W. (1978) New biopyriboles from Chester, Vermont: I. Descriptive mineralogy. American Mineralogist, 63 (9-10) 1000-1009

Veblen, David R., Burnham, Charles W. (1978) New biopyriboles from Chester, Vermont: II. The crystal chemistry of jimthompsonite, clinojimthompsonite, and chesterite, and the amphibole-mica reaction. American Mineralogist, 63 (11-12) 1053-1073

(2001) Jimthompsonite. Handbook of Mineralogy. Mineralogical Society of America

Localities for JimthompsoniteHide

Showing 10 localities.

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the

symbol to view information about a locality. The

symbol next to localities in the list can be used to jump to that position on the map.

Hide all sections | Show all sections

Locality ListHide

- This locality has map coordinates listed.

- This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality.

- Good crystals or important locality for species.

- World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). ~~Struck out~~ - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.


Finland
Southwest Finland Salo Kisko ⓘ Orijärvi deposit	Schumacher et al. (3-4)

Greenland
Sermersooq Nuuk ⓘ Isua Greenstone Belt (Isua Supercrustal Belt)	epsc.wustl.edu (2008)

Italy
Piedmont Verbano-Cusio-Ossola Province Montescheno ⓘ I Mondei (Ca' Mondei)	Piccoli et al. (2007)

Japan
Iwate Prefecture Hanamaki City ⓘ Mount Hayachine	Konishi et al (1991)

Norway
Nordland Meløy ⓘ Glomfjord	Rune S. Selbekk (2010)

Switzerland
Ticino ⓘ Agro Valley	Stalder et al. (1998)
Vallemaggia Lavizzara Fusio ⓘ Bena Alp	Stalder et al. (1998)
ⓘ Pizzo di Röd	Stalder et al. (1998)

UK
Scotland Highland North， West and Central Sutherland ⓘ Achmelvich dike	Droop (1994)

USA (TL)
Vermont Windsor County Chester ⓘ Carlton Quarry (TL)	Veblen et al. (1978) +1 other reference

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Jimthompsonite

About JimthompsoniteHide

Unique IdentifiersHide

IMA Classification of JimthompsoniteHide

Classification of JimthompsoniteHide

Mineral SymbolsHide

Physical Properties of JimthompsoniteHide

Optical Data of JimthompsoniteHide

Chemistry of JimthompsoniteHide

Crystallography of JimthompsoniteHide

Crystal StructureHide

X-Ray Powder DiffractionHide

Geological EnvironmentHide

Type Occurrence of JimthompsoniteHide

Synonyms of JimthompsoniteHide

Other Language Names for JimthompsoniteHide

Common AssociatesHide

Related Minerals - Strunz-mindat GroupingHide

Fluorescence of JimthompsoniteHide

Other InformationHide

Internet Links for JimthompsoniteHide

References for JimthompsoniteHide

Localities for JimthompsoniteHide

Locality ListHide

Related Minerals - Strunz-mindat Grouping Hide