Dumontite Mineral Data

General Dumontite Information

Chemical Formula:

Pb2(UO2)3O2(PO4)2•5(H2O)

Composition:

Molecular Weight = 1,536.50 gm

Uranium 46.47 % U 52.72 % UO₂

Phosphorus 4.03 % P 9.24 % P₂O₅

Hydrogen 0.66 % H 5.86 % H₂O

Lead 26.97 % Pb 29.05 % PbO

Oxygen 21.87 % O

______ ______

100.00 % 96.88 % = TOTAL OXIDE

Empirical Formula:

Pb₂(UO₂)₃O₂(PO₄)₂•5(H₂O)

Environment:

Secondary lead-uranium mineral

IMA Status:

Valid Species (Pre-IMA) 1924

Locality:

Kasolo (Shinkolobwe), Katanga (Shaba), Congo (Zaï¿½re) Link to MinDat.org Location Data.

Name Origin:

Named for A.H. Dumont

Name Pronunciation:

Dumontite + Pronunciation

Synonym:

ICSD 202795

PDF 12-158

Dumontite Image

Images:

Dumontite

Comments: Bright yellow acicular crystals of dumontite on matrix.
Location: Shinkolobwe mine, Tantara, Shaba, Democratic Republic of the Congo. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Dumontite Crystallography

Axial Ratios:

a:b:c =0.4877:1:0.4196

Cell Dimensions:

a = 8.16, b = 16.73, c = 7.02, Z = 2; beta = 110° V = 900.55 Den(Calc)= 5.67

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 2₁/m

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

By Intensity(I/I_o): 4.27(1), 2.94(0.85), 3(0.85),

Physical Properties of Dumontite

Cleavage:

{???} Perfect

Color:

Golden yellow, Light yellow.

Density:

5.65

Diaphaneity:

Translucent

Hardness:

2-3 - Gypsum-Calcite

Luminescence:

Fluorescent, Short UV=weak green, Long UV=weak green.

Streak:

light yellow

Optical Properties of Dumontite

Gladstone-Dale:

CI meas= -0.201 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.197 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1534,KPDmeas= 0.154,KC= 0.1282
Ncalc = 1.72 - 1.73

Optical Data:

Biaxial (+), a=1.85, b=1.87, g=1.89, bire=0.0400

Calculated Properties of Dumontite

Electron Density:

Bulk Density (Electron Density)=4.78 gm/cc
note: Specific Gravity of Dumontite =5.67 gm/cc.

Fermion Index:

Fermion Index = 0.06
Boson Index = 0.94

Photoelectric:

PE_Dumontite=1,741.15 barns/electron
U=PE_Dumontite x r_electron=8,327.07 barns/cc.

Radioactivity:

GRapi = 3,341,365.42 (Gamma Ray American Petroleum Institute Units)
Concentration of Dumontite per GRapi unit = 299.28 (PPB)

Dumontite 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) 9.10 ± 2.28 grams of pure Dumontite .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 910.31 ±227.58 grams of pure Dumontite .

**Estimated Radioactivity from Dumontite** - 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 / 6.96 cm	83,189,999	2.25E-03	3,341,365.42	1,098.53
100 gm / 3.23 cm	8,319,000	2.25E-04	334,136.54	109.85
10 gm / 1.50 cm	831,900	2.25E-05	33,413.65	10.99
1 gm / 6.96 mm	83,190	2.25E-06	3,341.37	1.10
0.1 gm / 3.23 mm	8,319	2.25E-07	334.14	0.11
0.01 gm / 1.50 mm	832	2.25E-08	33.41	0.01
0.001 gm / 0.70 mm	83	2.25E-09	3.34	0.00

Weight of pure Dumontite in grams (gm) and Calculated Diameter of a Sphere with a Density of 5.67 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

Dumontite Classification

Dana Class:

42.04.05.01 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen

(42.04)where (AB)5 (XO4)2 Zq ï¿½ x(H2O)

(42.04.05)Dumontite Group

42.04.05.01 Dumontite Pb2(UO2)3O2(PO4)2•5(H2O) P 2₁/m 2/m

42.04.05.02 Hugelite Pb2(UO2)3(AsO4)2(OH)4•3(H2O) P 2₁/m 2/m

42.04.05.03 Bergenite Ca2Ba4[(UO3)2O2(PO4)2]3(H2O)16 P 2₁/c 2/m

Strunz Class:

08.EC.15 08 - PHOSPHATES, ARSENATES, VANADATES

08.E - Uranyl Phosphates and Arsenates

08.EC -UO2:RO4 = 3:2

08.EC.15 Dumontite Pb2(UO2)3O2(PO4)2•5(H2O) P 2₁/m 2/m

08.EC.15 Hugelite Pb2(UO2)3(AsO4)2(OH)4•3(H2O) P 2₁/m 2/m

Other Dumontite Information

References:

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

See Also:

Links to other databases for Dumontite :
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
16 - WWW-MINCRYST

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Dumontite

Pb2(UO2)3O2(PO4)2•5(H2O)
Dana No: 42.04.05.01 Strunz No: 08.EC.15
Locality:

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