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Weeksite Mineral Data

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General Weeksite Information

Help on Chemical  Formula: Chemical Formula: K2(UO2)2Si6O15•4(H2O)
Help on Composition: Composition: Molecular Weight = 1,028.91 gm
   Potassium   4.18 %  K     5.04 % K2O
   Barium      4.00 %  Ba    4.47 % BaO
   Calcium     0.39 %  Ca    0.55 % CaO
   Uranium    48.58 %  U    55.11 % UO2
   Silicon    13.65 %  Si   29.20 % SiO2
   Hydrogen    0.27 %  H     2.45 % H2O
   Oxygen     28.92 %  O
             ______        ______ 
             100.00 %       96.81 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: K1.1Ba0.3Ca0.1(UO2)2.1Si5O13•1.4(H2O)
Help on Environment: Environment: In "opal" veinlets in rhyolite and agglomerates, as well as in sandstones and limestones.
Help on IMA Status: IMA Status: Approved IMA 1960
Help on Locality: Locality: Autunite No. 8 claim, Thomas Range, Juab County, Utah, USA. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Mary Alice Dowse Weeks (1909-1988), mineralogist with the U.S. Geological Survey, noted specialist in the mineralogy of uranium and vanadium.
Help on Name Pronunciation: Name Pronunciation: Weeksite Say WEEKSITE
Help on Synonym: Synonym: ICSD 63515
  PDF 12-462

Weeksite Image

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Comments: Bright yellow weeksite aggregates.
Location: Anderson mine, Yavapai County, Arizona, USA. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

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Comments: Globular masses of yellow weeksite crystals with white aragonite on a sandstone matrix.
Location: Jackpile Mine, Laguna District, Cibola County, New Mexico, USA. Scale: Picture size 1 cm.
© Paul M. Schumacher

Weeksite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.9972:1:2.5174
Help on Cell Dimensions: Cell Dimensions: a = 14.209, b = 14.248, c = 35.869, Z = 16; V = 7,261.67 Den(Calc)= 3.76
Help on Crystal System: Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: C mmb
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 7.11(1), 5.57(0.9), 8.98(0.8),

Physical Properties of Weeksite

Help on Cleavage: Cleavage: {hk0} Distinct, {hk0} Distinct
Help on Color: Color: Yellow.
Help on Density: Density: 4.1
Help on Diaphaneity: Diaphaneity: Transparent to Translucent
Help on Habit: Habit: Acicular - Occurs as needle-like crystals.
Help on Habit: Habit: Bladed - Aggregates of thin lath-like crystals (e.g. kyanite).
Help on Habit: Habit: Platy - Sheet forms (e.g. micas).
Help on Hardness: Hardness: 1-2 - Between Talc and Gypsum
Help on Luminescence: Luminescence: Radioactive.
Help on Luster: Luster: Waxy
Help on Streak: Streak: yellow

Optical Properties of Weeksite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.041 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.136 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.16,KPDmeas= 0.1467,KC= 0.1409
Ncalc = 1.53 - 1.58
Help on Optical Data: Optical Data: Biaxial (-), a=1.596, b=1.603, g=1.606, bire=0.0100, 2V(Calc)=66, 2V(Meas)=~60. Dispersion r > v strong.
Help on Pleochroism (x): Pleochroism (x): colorless.
Help on Pleochroism (y): Pleochroism (y): pale yellow green.
Help on Pleochroism (z): Pleochroism (z): yellow green.

Calculated Properties of Weeksite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.62 gm/cc
note: Specific Gravity of Weeksite =4.10 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEWeeksite =1,266.86 barns/electron
U=PEWeeksite x relectron=4,588.80 barns/cc.
Help on Radioactivity: Radioactivity:

GRapi = 3,658,435.27 (Gamma Ray American Petroleum Institute Units)
Concentration of Weeksite per GRapi unit = 273.34 (PPB)

Weeksite is Radioactive as defined in 49 CFR 173.403. Greater than 70 Bq / gram.

Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 10 cm box) 8.31 ± 2.08 grams of pure Weeksite .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 831.41 ±207.85 grams of pure Weeksite .

Estimated Radioactivity from Weeksite - very strong
Curies (Ci)
If Held in Hand
For One Hour
1000 gm / 7.75 cm 86,962,009 2.35E-03 3,658,435.27 1,202.77
100 gm / 3.60 cm 8,696,201 2.35E-04 365,843.53 120.28
10 gm / 1.67 cm 869,620 2.35E-05 36,584.35 12.03
1 gm / 7.75 mm 86,962 2.35E-06 3,658.44 1.20
0.1 gm / 3.60 mm 8,696 2.35E-07 365.84 0.12
0.01 gm / 1.67 mm 870 2.35E-08 36.58 0.01
0.001 gm / 0.78 mm 87 2.35E-09 3.66 0.00

Weight of pure Weeksite in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.10 gm/cc.*
Goverment Estimate of Average Annual Exposure ( 360 mRem) **
Note: 10 microsieverts/hr = 1 mRem/hr **
Max Permissable Adult Dose 50,000 mRem/yr (hands), 15,000 mRem/yr (eyes)
Lethal Dose LD(50) Exposure 400,000 to 500,000 mRem

Weeksite Classification

Help on  Dana Class: Dana Class: (53)Nesosilicate Insular SiO4 Groups and Other Anions of Complex Cations
  (53.03)with (UO2)
  (53.03.02)Weeksite group Weeksite K2(UO2)2Si6O15•4(H2O) C mmb 2/m 2/m 2/m Haiweeite Ca[(UO2)2Si5O12(OH)2]•3(H2O) C mcm 2/m 2/m 2/m Metahaiweeite Ca(UO2)2Si6O15•n(H2O),n<5 P 2/c ? 2/m Coutinhoite! ThxBa1-2x(H2O)y(UO2)2Si5O13•H2O C mmb 2/m 2/m 2/m
Help on  Strunz Class: Strunz Class: 09.AK.30 09 - SILICATES (Germanates)
  09.A - Nesosilicates
  09.AK -Uranyl neso- and polysilicates
09.AK.30 Weeksite K2(UO2)2Si6O15•4(H2O) C mmb 2/m 2/m 2/m
09.AK.30 Coutinhoite! ThxBa1-2x(H2O)y(UO2)2Si5O13•H2O C mmb 2/m 2/m 2/m

Other Weeksite Information

Help on References: References: NAME( AntBidBlaNic2) PHYS. PROP.(AntBidBlaNic2, AmMin, Vol 86, p 1115) OPTIC PROP.(AntBidBlaNic2)
Help on See Also: See Also: Links to other databases for Weeksite :
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
15 - Uranium Minerals

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Dana No: Strunz No: 09.AK.30





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