Minnesotaite Mineral Data

Minnesotaite Mineral Data +

General Minnesotaite Information

Chemical Formula:

(Fe++,Mg)3Si4O10(OH)2

Composition:

Molecular Weight = 458.12 gm

Magnesium 2.65 % Mg 4.40 % MgO

Iron 30.48 % Fe 39.21 % FeO

Silicon 24.52 % Si 52.46 % SiO₂

Hydrogen 0.44 % H 3.93 % H₂O

Oxygen 41.91 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Fe²⁺_2.5Mg_0.5Si₄O₁₀(OH)₂

IMA Status:

Valid Species (Pre-IMA) 1944

Locality:

Link to MinDat.org Location Data.

Name Origin:

Named after its occurrence in Minnesota, USA.

Synonym:

Iron Talc

Minnesotaite Image

Images:

Minnesotaite

Comments: Greenish-gray dull minnesotaite masses in iron ore matrix.
Location: Virginia, Saint Louis County, Minnesota, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Minnesotaite Crystallography

Axial Ratios:

a:b:c =0.5969:1:1.0217

Cell Dimensions:

a = 5.623, b = 9.419, c = 9.624, Z = 2; alpha = 85.21°, beta = 95.64°, gamma = 90° V = 505.48 Den(Calc)= 3.01

Crystal System:

Triclinic - PinacoidalH-M Symbol ( 1) Space Group: C1

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

By Intensity(I/I_o): 9.54(1), 2.53(0.7), 3.18(0.5),

Physical Properties of Minnesotaite

Cleavage:

[001] Perfect

Color:

Pale green.

Density:

3.01

Diaphaniety:

Translucent

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Habit:

Foliated - Two dimensional platy forms.

Habit:

Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)

Hardness:

1.5-2 - Talc-Gypsum

Luster:

Pearly

Streak:

white

Optical Properties of Minnesotaite

Gladstone-Dale:

CI meas= 0.028 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.028 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1993,KPDmeas= 0.1993,KC= 0.205

Optical Data:

Biaxial (-), a=1.578-1.583, b=1.578-1.622, g=1.615-1.623, bire=0.0370-0.0400, 2V(Calc)=0-16, 2V(Meas)=4.

Pleochroism (x):

colorless or pale yellow.

Pleochroism (y):

colorless or pale green.

Pleochroism (z):

colorless or pale green.

Calculated Properties of Minnesotaite

Electron Density:

r_electron=2.96 gm/cc
note: r_Minnesotaite=3.01 gm/cc.

Fermion Index

Fermion Index = 0.02076
Boson Index = 0.97924

Photoelectric:

PE_Minnesotaite= 10.04 barns/electron
U=PE_Minnesotaite x r_electron= 29.68 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Minnesotaite is Not Radioactive

Minnesotaite Classification

Dana Class:

71.2.1.5 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.2)with 2:1 Layers

(71.2.1)Pyrophyllite-talc group

71.2.1.1 Pyrophyllite Al2Si4O10(OH)2 P1 1

71.2.1.2 Ferripyrophyllite Fe2Si4O10(OH)2 C 2/m 2/m

71.2.1.3 Talc Mg3Si4O10(OH)2 C 2/c 2/m

71.2.1.4 Willemseite (Ni,Mg)3Si4O10(OH)2 C 2/c 2/m

71.2.1.5 Minnesotaite (Fe,Mg)3Si4O10(OH)2 C1 1

71.2.1.6 Brinrobertsite! (Na,K,Ca)x(Al,Fe,Mg)4(Si,Al)8O20(OH)4·3.54(H2O)[x=0.35,n=3.54] pseudo 2/m 2/m

Strunz Class:

VIII/H.09-50 VIII - Silicates

VIII/H - Phyllosilicates (layered) Mica like layered silicates with [Si4O10]4- and related groups

VIII/H.09 - Talc series

VIII/H.09-10 Pyrophyllite Al2Si4O10(OH)2 P1 1

VIII/H.09-20 Ferripyrophyllite Fe2Si4O10(OH)2 C 2/m 2/m

VIII/H.09-30 Macaulayite (Fe,Al)24Si4O43(OH)2 C? Mono

VIII/H.09-40 Talc Mg3Si4O10(OH)2 C 2/c 2/m

VIII/H.09-50 Minnesotaite (Fe,Mg)3Si4O10(OH)2 C1 1

VIII/H.09-60 Willemseite (Ni,Mg)3Si4O10(OH)2 C 2/c 2/m

VIII/H.09-65 Pimelite Ni3Si4O10(OH)2·4(H2O) Unk. Hex

VIII/H.09-70 Kegelite Pb8Al4Si8O20(SO4)2(CO3)4(OH)8 A2/m,A2,Am Mono

Other Minnesotaite Information

References:

NAME( Heinrich65) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)

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

Minnesotaite

(Fe++,Mg)3Si4O10(OH)2
Dana No: 71.2.1.5 Strunz No: VIII/H.09-50
Locality:

Notes: