Dumontite Mineral Data

Dumontite Mineral Data +

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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 (Zaïre) Link to MinDat.org Location Data.

Name Origin:

Named for A.H. Dumont

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 - PrismaticH-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),

Crystal Structure:

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Piret P , Piret-Meunier J , Bulletin de Mineralogie , 111 (1988) p.439-442, Nouvelle determination de la structure cristalline, de la dumonite Pb2[(UO2)3O2(PO4)2]*5H2O, Locality: Shinkolobwe, Shaba, Zaire

Physical Properties of Dumontite

Cleavage:

[???] Perfect

Color:

Golden yellow, Light yellow.

Density:

5.65

Diaphaniety:

Translucent

Hardness:

2-3 - Gypsum-Calcite

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

Optical Data:

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

Calculated Properties of Dumontite

Electron Density:

r_electron=4.78 gm/cc
note: r_Dumontite=5.67 gm/cc.

Fermion Index

Fermion Index = 0.06305
Boson Index = 0.93695

Photoelectric:

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

Radioactivity:

GRapi = 3,341,364.04 (Gamma Ray American Petroleum Institute Units)

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	3,341,364.04	1,098.53
100 gm / 3.23 cm	8,319,000	2.25E-04	334,136.40	109.85
10 gm / 1.50 cm	831,900	2.25E-05	33,413.64	10.99
1 gm / 6.96 mm	83,190	2.25E-06	3,341.36	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:

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

(42.4)where (AB)5 (XO4)2 Zq · x(H2O)

(42.4.5)Dana Group

42.4.5.1 Dumontite Pb2(UO2)3O2(PO4)2·5(H2O) P 2₁/m 2/m

42.4.5.2 Hugelite Pb2(UO2)3(AsO4)2(OH)4·3(H2O) P 2₁/m 2/m

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

Strunz Class:

VII/E.07-90 VII - Phosphates, Arsenates and Vanadates

VII/E - Uranylphosphates and uranylvanadates with [UO2]2+ - [PO4 | AsO4]3- and [UO2]2+ - [V2O8]6-

VII/E.07 - Phosphuranylite series

VII/E.07-10 Phuralumite Al2(UO2)3(PO4)2(OH)6·10(H2O) P 2₁/a 2/m

VII/E.07-20 Mundite Al(UO2)3(PO4)2(OH)3·5(H2O) P 2₁cn,Pmcn Ortho

VII/E.07-25 Yingjiangite (K2,Ca)(UO2)7(PO4)4(OH)6·6(H2O) Bmmb 2/m 2/m 2/m

VII/E.07-30 Phosphuranylite KCa(H3O)3(UO2)7(PO4)4O4·8(H2O) C mcm 2/m 2/m 2/m

VII/E.07-40 Phurcalite Ca2(UO2)3O2(PO4)2·7(H2O) P bca 2/m 2/m 2/m

VII/E.07-50 Arsenuranylite Ca(UO2)4(AsO4)2(OH)4·6(H2O) Bmmb 2/m 2/m 2/m

VII/E.07-60 Bergenite Ca2Ba4[(UO3)2O2(PO4)2]3(H2O)16 P 2₁/c 2/m

VII/E.07-70 Francoisite-(Nd) (Nd,Y,Sm,Ce)(UO2)3(PO4)2O(OH)·6(H2O) P 2₁/c 2/m

VII/E.07-80 Dewindtite Pb3[H(UO2)3O2(PO4)2]2·12(H2O) Bmmb 2/m 2/m 2/m

VII/E.07-90 Dumontite Pb2(UO2)3O2(PO4)2·5(H2O) P 2₁/m 2/m

VII/E.07-100 Hugelite Pb2(UO2)3(AsO4)2(OH)4·3(H2O) P 2₁/m 2/m

VII/E.07-110 Kamitugaite PbAl(UO2)5(PO4)2(OH)9·9.5(H2O) P1,P 1 Tri

VII/E.07-120 Kivuite? (Th,Ca,Pb)H2(UO2)4(PO4)2(OH)8·7(H2O) Unk Ortho

VII/E.07-130 Althupite ThAl(UO2)7(PO4)4(OH)5·15(H2O) P1 1

VII/E.07-140 Vanmeersscheite U(UO2)3(PO4)2(OH)6·4(H2O) P mn2₁ mm2

VII/E.07-150 Metavanmeersscheite U(UO2)3(PO4)2(OH)6·2(H2O) F dd2 mm2

Other Dumontite Information

References:

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

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Dumontite

Pb2(UO2)3O2(PO4)2·5(H2O)
Dana No: 42.4.5.1 Strunz No: VII/E.07-90
Locality:

Notes: