Chadwickite Mineral Data

General Chadwickite Information

Chemical Formula:

(UO2)H(AsO3)

Composition:

Molecular Weight = 393.96 gm

Uranium 60.42 % U 68.54 % UO₂

Arsenic 19.02 % As 25.11 % As₂O₃

Hydrogen 0.26 % H 2.29 % H₂O

Oxygen 20.31 % O

______ ______

100.00 % 95.94 % = TOTAL OXIDE

Empirical Formula:

(UO₂)H(AsO₃)

Environment:

From granite in dump material at the Sophia mine, central Black Forest.

IMA Status:

Approved IMA 1998 (Dana # Added)

Locality:

Wittichen in the Black Forest, Aufschluss, Germany. Link to MinDat.org Location Data.

Name Origin:

Named after Sir James Chadwick (1891-1974), English physicist Cavendish Laboratory, University of Cambridge, U.K. 1935 Nobel Prize winner for his discovery of the neutron.

Synonym:

ICSD 266

IMA1997-005

PDF 34-1170

Chadwickite Crystallography

Axial Ratios:

a:c = 1:1.4509

Cell Dimensions:

a = 11, c = 15.96, Z = 14; V = 1,931.16 Den(Calc)= 4.74

Crystal System:

Tetragonal

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

By Intensity(I/I_o): 4.95(1), 3.33(0.8), 5.58(0.8),

Physical Properties of Chadwickite

Cleavage:

{001} Perfect

Color:

Yellow.

Density:

4.86

Diaphaneity:

Translucent

Fracture:

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

Habit:

Encrustations - Forms crust-like aggregates on matrix.

Hardness:

2 - Gypsum

Luster:

Earthy (Dull)

Streak:

yellow

Optical Properties of Chadwickite

Gladstone-Dale:

CI meas= -0.209 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.239 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1677,KPDmeas= 0.1636,KC= 0.1353
Ncalc = 1.64 - 1.66

Optical Data:

Uniaxial (-), e=1.75, w=1.84, bire=0.0900.

Calculated Properties of Chadwickite

Electron Density:

Bulk Density (Electron Density)=4.10 gm/cc
note: Specific Gravity of Chadwickite =4.86 gm/cc.

Fermion Index:

Fermion Index = 0.0044481118
Boson Index = 0.9955518882

Photoelectric:

PE_Chadwickite=1,641.17 barns/electron
U=PE_Chadwickite x r_electron=6,721.72 barns/cc.

Radioactivity:

GRapi = 4,340,175.65 (Gamma Ray American Petroleum Institute Units)
Concentration of Chadwickite per GRapi unit = 230.41 (PPB)

Chadwickite 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) 7.01 ± 1.75 grams of pure Chadwickite .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 700.82 ±175.20 grams of pure Chadwickite .

**Estimated Radioactivity from Chadwickite** - very strong
Specimen Size Weight/Volume (Sphere) *	Calculated Activity Bequerols (Bq)	Calculated Activity Curies (Ci)	Estimated Activity GR(api)	Estimated Exposure (mRem**)/hr If Held in Hand For One Hour
1000 gm / 7.32 cm	108,152,265	2.92E-03	4,340,175.65	1,426.91
100 gm / 3.40 cm	10,815,227	2.92E-04	434,017.57	142.69
10 gm / 1.58 cm	1,081,523	2.92E-05	43,401.76	14.27
1 gm / 7.32 mm	108,152	2.92E-06	4,340.18	1.43
0.1 gm / 3.40 mm	10,815	2.92E-07	434.02	0.14
0.01 gm / 1.58 mm	1,082	2.92E-08	43.40	0.01
0.001 gm / 0.73 mm	108	2.92E-09	4.34	0.00

Weight of pure Chadwickite in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.86 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

Chadwickite Classification

Dana Class:

45.01.15.01 (45)Acid and normal Antimonites, Arsenites and Phosphites

(45.01)with miscellaneous formulae

(45.01.15)Dana Group

45.01.15.01 Chadwickite! (UO2)H(AsO3) Tetra

Strunz Class:

04.JA.60 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.J - Arsenites, Antimonites, Bismuthites, Sulfites,

04.JA -Arsenites, antimonites, bismuthites; without additional anions, without H2O

04.JA.60 Chadwickite! (UO2)H(AsO3) Tetra

Other Chadwickite Information

References:

NAME( AmMin, Vol. 84, No. 7-8) PHYS. PROP.(Eur. J. Min.,Vol.10,1998) OPTIC PROP.(Eur. J. Min.,Vol.10,1998)

See Also:

Links to other databases for Chadwickite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - Handbook of Mineralogy (UofA)
7 - MinDAT
8 - Mineralienatlas (Deutsch)
9 - Online Mineral Museum
10 - QUT Mineral Atlas
11 - Ruff.Info
12 - Uranium Minerals

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Chadwickite

(UO2)H(AsO3)
Dana No: 45.01.15.01 Strunz No: 04.JA.60
Locality:

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