Threadgoldite Mineral Data

General Threadgoldite Information

Chemical Formula:

Al(UO2)2(PO4)2(OH)•8(H2O)

Composition:

Molecular Weight = 918.11 gm

Uranium 51.85 % U 58.82 % UO₂

Aluminum 2.94 % Al 5.55 % Al₂O₃

Phosphorus 6.75 % P 15.46 % P₂O₅

Hydrogen 1.87 % H 16.68 % H₂O

Oxygen 36.60 % O

______ ______

100.00 % 96.51 % = TOTAL OXIDE

Empirical Formula:

Al(UO₂)₂(PO₄)₂(OH)•8(H₂O)

Environment:

The P analog of metavanuralite.

IMA Status:

Approved IMA 1979

Locality:

Kobokobo, Kivu, Zaire. Link to MinDat.org Location Data.

Name Origin:

Named for Ian M. Threadgold (1929-), University of Sydney, NSW, Australia.

Name Pronunciation:

Threadgoldite + Pronunciation

Synonym:

ICSD 31265

PDF 33-39

Threadgoldite Image

Images:

Threadgoldite

Comments: Beige threadgoldite filling cracks in, and coating, black uraninite. Schumacher Collection.
Location: Kobokobo Pegmatite, Lusungu River District, Kivu, Congo (ZaÃ¯re). Scale: Picture size 5 mm.
© Paul M. Schumacher

Threadgoldite Crystallography

Axial Ratios:

a:b:c =2.0558:1:2.005

Cell Dimensions:

a = 20.25, b = 9.85, c = 19.75, Z = 8; beta = 111.4° V = 3,667.79 Den(Calc)= 3.33

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/c

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

By Intensity(I/I_o): 9.43(1), 3.474(0.8), 3.366(0.6),

Physical Properties of Threadgoldite

Cleavage:

{???} Perfect

Color:

Greenish yellow.

Density:

3.4

Diaphaneity:

Translucent

Habit:

Micaceous - Platy texture with "flexible" plates.

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

2-3 - Gypsum-Calcite

Luminescence:

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

Streak:

yellow white

Optical Properties of Threadgoldite

Gladstone-Dale:

CI meas= -0.101 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.124 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1746,KPDmeas= 0.171,KC= 0.1553
Ncalc = 1.52 - 1.53

Optical Data:

Biaxial (-), a=1.573, b=1.583, g=1.588, bire=0.0150, 2V(Calc)=70, 2V(Meas)=70.

Pleochroism (x):

colorless.

Pleochroism (z):

pale yellow.

Calculated Properties of Threadgoldite

Electron Density:

Bulk Density (Electron Density)=3.05 gm/cc
note: Specific Gravity of Threadgoldite =3.40 gm/cc.

Fermion Index:

Fermion Index = 0.0039118007
Boson Index = 0.9960881993

Photoelectric:

PE_{Threadgoldite}=1,311.25 barns/electron
U=PE_{Threadgoldite} x r_electron=4,001.28 barns/cc.

Radioactivity:

GRapi = 3,966,723.37 (Gamma Ray American Petroleum Institute Units)
Concentration of Threadgoldite per GRapi unit = 252.10 (PPB)

Threadgoldite 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) 7.67 ± 1.92 grams of pure Threadgoldite .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 766.80 ±191.70 grams of pure Threadgoldite .

**Estimated Radioactivity from Threadgoldite** - 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 / 8.25 cm	92,815,040	2.51E-03	3,966,723.37	1,304.13
100 gm / 3.83 cm	9,281,504	2.51E-04	396,672.34	130.41
10 gm / 1.78 cm	928,150	2.51E-05	39,667.23	13.04
1 gm / 8.25 mm	92,815	2.51E-06	3,966.72	1.30
0.1 gm / 3.83 mm	9,282	2.51E-07	396.67	0.13
0.01 gm / 1.78 mm	928	2.51E-08	39.67	0.01
0.001 gm / 0.83 mm	93	2.51E-09	3.97	0.00

Weight of pure Threadgoldite in grams (gm) and Calculated Diameter of a Sphere with a Density of 3.40 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

Threadgoldite Classification

Dana Class:

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

(42.11)where (AB)4 (XO4)3 Zq ï¿½ x(H2O)

(42.11.13)Vanuralite Group

42.11.13.01 Vanuralite Al(UO2)2(VO4)2(OH)•11(H2O) A2/a 2/m

42.11.13.02 Metavanuralite Al(UO2)2(VO4)2(OH)•8(H2O) P 1or P1 Tri

42.11.13.03 Threadgoldite Al(UO2)2(PO4)2(OH)•8(H2O) C 2/c 2/m

42.11.13.04 Chistyakovaite-(Y)! Al(UO2)2(AsO4)2(F,OH)•6.5H2O P 2/m, P 2 or Pm Mono

Strunz Class:

08.EB.20 08 - PHOSPHATES, ARSENATES, VANADATES

08.E - Uranyl Phosphates and Arsenates

08.EB -UO2:RO4 = 1:1

08.EB.20 Threadgoldite Al(UO2)2(PO4)2(OH)•8(H2O) C 2/c 2/m

08.EB.20 Chistyakovaite-(Y)! Al(UO2)2(AsO4)2(F,OH)•6.5H2O P 2/m, P 2 or Pm Mono

Other Threadgoldite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Threadgoldite :
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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Threadgoldite

Al(UO2)2(PO4)2(OH)•8(H2O)
Dana No: 42.11.13.03 Strunz No: 08.EB.20
Locality:

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