Straczekite Mineral Data

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General Straczekite Information

Chemical Formula:

(Ca,K,Ba)(V5+,V4+)8O20•3H2O

Composition:

Molecular Weight = 831.07 gm

Potassium 1.41 % K 1.70 % K₂O

Barium 1.65 % Ba 1.84 % BaO

Calcium 2.89 % Ca 4.05 % CaO

Vanadium 49.04 % V 19.96 % VO₂ / 65.65 % V₂O₅

Hydrogen 0.73 % H 6.50 % H₂O

Oxygen 44.28 % O

______ ______

100.00 % 99.71 % = TOTAL OXIDE

Empirical Formula:

Ca_0.6K_0.3Ba_0.1V⁵⁺₆V⁴⁺₂O₂₀•3(H₂O)

IMA Status:

Approved IMA 1983

Locality:

Union Carbide mine, Wilson Springs, Arkansas, USA Link to MinDat.org Location Data.

Name Origin:

Named for John A. Straczed (1914-), U. S. Geologist.

Name Pronunciation:

Straczekite + Pronunciation

Straczekite Image

Images:

Straczekite

Comments: Greenish-black, prismatic-acicular crystals of straczekite.
Location: Union Carbide Mine, Wilson Springs (Potash Sulfur Springs), Garland Co., Arkansas, USA. Scale: Picture size 1.5 mm.
© Thomas Witzke / Abraxas-Verlag

Straczekite Crystallography

Axial Ratios:

a:b:c =3.1902:1:2.9053

Cell Dimensions:

a = 11.679, b = 3.6608, c = 10.636, Z = 1; beta = 100.53° V = 447.08 Den(Calc)= 3.09

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/m

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

By Intensity(I/I_o): 3.486(1), 1.8306(0.5), 10.449(0.5),

Crystal Structure:

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Kutoglu A , Zeitschrift fur Kristallographie , 162 (1983) p.263-272, Kristallstruktur der calcium-vanadium-bronze CaxV4+2xV5+(2-2x)O5, Locality: synthetic, Note: z(Ca1) and z(O5) corrected

Physical Properties of Straczekite

Cleavage:

{100} Perfect

Color:

Greenish black.

Density:

3.19 - 3.21, Average = 3.2

Habit:

Fibrous - Crystals made up of fibers.

Habit:

Microscopic Crystals - Crystals visible only with microscopes.

Hardness:

1-2 - Between Talc and Gypsum

Luster:

Greasy (Oily)

Streak:

greenish black

Optical Properties of Straczekite

Gladstone-Dale:

CI meas= 0.075 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= 0.042 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.3236,KPDmeas= 0.3125,KC= 0.338
Ncalc = 2.04 - 2.08

Optical Data:

Biaxial (-), a=2, 2V(Meas)=large.

Pleochroism (x):

green.

Pleochroism (y):

green.

Pleochroism (z):

green.

Calculated Properties of Straczekite

Electron Density:

Bulk Density (Electron Density)=2.95 gm/cc
note: Specific Gravity of Straczekite =3.09 gm/cc.

Fermion Index:

Fermion Index = 0.0044252129
Boson Index = 0.9955747871

Photoelectric:

PE_Straczekite= 16.88 barns/electron
U=PE_Straczekite x r_electron= 49.88 barns/cc.

Radioactivity:

GRapi = 19.49 (Gamma Ray American Petroleum Institute Units)
Concentration of Straczekite per GRapi unit = 5.13 (%)

Estimated Radioactivity from Straczekite - barely detectable

Straczekite Classification

Dana Class:

47.03.02.01 (47)Vanadium Oxysalts

(47.03)(Hydrated)

(47.03.02)Straczekite Group

47.03.02.01 Straczekite (Ca,K,Ba)(V5,V4)8O20•3H2O C 2/m 2/m

47.03.02.02 Corvusite (Na,Ca,K)V8O20•4(H2O) C 2/m 2/m

47.03.02.03 Fernandinite CaV8O20•4(H2O) C 2/m 2/m

47.03.02.04 Bariandite Al0.6V8O20•9(H2O) C 2/c 2/m

47.03.02.05 Bokite (Al,Fe)1.3(V,Fe)8O20•4.7(H2O) C 2/m 2/m

47.03.02.06 Kazakhstanite Fe5V3V12O39(OH)9•9(H2O) C 2/m 2/m

Strunz Class:

04.HE.20 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.H - V[5,6] Vanadates

04.HE -Phyllovanadates

04.HE.20 Bokite (Al,Fe)1.3(V,Fe)8O20•4.7(H2O) C 2/m 2/m

04.HE.20 Bariandite Al0.6V8O20•9(H2O) C 2/c 2/m

04.HE.20 Corvusite (Na,Ca,K)V8O20•4(H2O) C 2/m 2/m

04.HE.20 Fernandinite CaV8O20•4(H2O) C 2/m 2/m

04.HE.20 Straczekite (Ca,K,Ba)(V5,V4)8O20•3H2O C 2/m 2/m

Other Straczekite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8)

See Also:

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

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Straczekite

(Ca,K,Ba)(V5+,V4+)8O20•3H2O
Dana No: 47.03.02.01 Strunz No: 04.HE.20
Locality:

Notes: