Coffinite Mineral Data

General Coffinite Information

Chemical Formula:

U(SiO4)1-x(OH)4x

Composition:

Molecular Weight = 327.71 gm

Uranium 72.63 % U 82.40 % UO₂

Silicon 7.71 % Si 16.50 % SiO₂

Hydrogen 0.12 % H 1.10 % H₂O

Oxygen 19.53 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

U(SiO₄)_0.9(OH)_0.4

Environment:

In Colorado Plateau-type black unoxidized U-V deposits, replacing organic material in sandstone.

IMA Status:

Valid Species (Pre-IMA) 1956

Locality:

La Sal No. 2 mine, Beaver Mesa, Gateway district, Mesa County, New Mexico, USA. Link to MinDat.org Location Data.

Name Origin:

Named for Reuben Clare Coffin (1886-1972), Tulsa, Oklahoma, USA, pioneer geologist in the study of uranium deposits of the Colorado Plateau.

Synonym:

ICSD 15484

PDF 11-420

Coffinite Image

Images:

Coffinite

Comments: Black, interstitial coffinite cementing a sub-angular quartzose sandstone. Schumacher Collection.
Location: Temple Mountain, San Rafael District (San Rafael Swell), Emery Co., Utah, USA. Scale: Picture size 5 mm.
© Paul M. Schumacher

Coffinite Crystallography

Axial Ratios:

a:c = 1:0.90187

Cell Dimensions:

a = 6.93, c = 6.25, Z = 3; V = 300.16 Den(Calc)= 5.44

Crystal System:

Tetragonal - Ditetragonal Dipyramidal H-M Symbol (4/m 2/m 2/m) Space Group: I 4₁/amd

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

By Intensity(I/I_o): 3.47(1), 4.66(1), 2.64(0.7),

Physical Properties of Coffinite

Cleavage:

None

Color:

Black, Pale brown, Dark brown.

Density:

5.1

Diaphaneity:

Subtranslucent to Opaque

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Hardness:

5-6 - Between Apatite and Orthoclase

Luster:

Subadamantine

Streak:

grayish black

Optical Properties of Coffinite

Gladstone-Dale:

CI meas= -0.205 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.129 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.136,KPDmeas= 0.1451,KC= 0.1205
Ncalc = 1.61 - 1.66

Optical Data:

Uniaxial (+/-), a=1.73-1.75, b=1.73-1.75, bire=0.0000.

Calculated Properties of Coffinite

Electron Density:

Bulk Density (Electron Density)=4.55 gm/cc
note: Specific Gravity of Coffinite =5.44 gm/cc.

Fermion Index:

Fermion Index = 0.0089257303
Boson Index = 0.9910742697

Photoelectric:

PE_Coffinite=1,971.22 barns/electron
U=PE_Coffinite x r_electron=8,965.99 barns/cc.

Radioactivity:

GRapi = 5,176,587.32 (Gamma Ray American Petroleum Institute Units)
Concentration of Coffinite per GRapi unit = 193.18 (PPB)

Coffinite 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) 5.88 ± 1.47 grams of pure Coffinite .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 587.58 ±146.90 grams of pure Coffinite .

**Estimated Radioactivity from Coffinite** - 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 / 7.05 cm	130,016,209	3.51E-03	5,176,587.32	1,701.89
100 gm / 3.27 cm	13,001,621	3.51E-04	517,658.73	170.19
10 gm / 1.52 cm	1,300,162	3.51E-05	51,765.87	17.02
1 gm / 7.05 mm	130,016	3.51E-06	5,176.59	1.70
0.1 gm / 3.27 mm	13,002	3.51E-07	517.66	0.17
0.01 gm / 1.52 mm	1,300	3.51E-08	51.77	0.02
0.001 gm / 0.71 mm	130	3.51E-09	5.18	0.00

Weight of pure Coffinite in grams (gm) and Calculated Diameter of a Sphere with a Density of 5.44 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

Coffinite Classification

Dana Class:

51.05.02.04 (51)Nesosilicate Insular SiO4 Groups Only

(51.05)with cations in >[6] coordination

(51.05.02)Zircon group

51.05.02.01 Zircon ZrSiO4 I 4₁/amd 4/m 2/m 2/m

51.05.02.02 Hafnon HfSiO4 I 4₁/amd 4/m 2/m 2/m

51.05.02.03 Thorite ThSiO4 I 4₁/amd 4/m 2/m 2/m

51.05.02.04 Coffinite U(SiO4)1-x(OH)4x I 4₁/amd 4/m 2/m 2/m

51.05.02.05 Thorogummite Th(SiO4)1-x(OH)4x I 4₁/amd 4/m 2/m 2/m

51.05.02.06 IMA2008-035! CeSiO4 I 4₁/amd 4mm

Strunz Class:

09.AD.30 09 - SILICATES (Germanates)

09.A - Nesosilicates

09.AD -Nesosilicates without additional anions;

09.AD.30 Coffinite U(SiO4)1-x(OH)4x I 4₁/amd 4/m 2/m 2/m

09.AD.30 Hafnon HfSiO4 I 4₁/amd 4/m 2/m 2/m

09.AD.30 Thorite ThSiO4 I 4₁/amd 4/m 2/m 2/m

09.AD.30 Thorogummite Th(SiO4)1-x(OH)4x I 4₁/amd 4/m 2/m 2/m

09.AD.30 Zircon ZrSiO4 I 4₁/amd 4/m 2/m 2/m

09.AD.30 IMA2008-035! CeSiO4 I 4₁/amd 4mm

Other Coffinite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Coffinite :
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 - University of Colorado - Mineral Structure Data
16 - Uranium Minerals
17 - WWW-MINCRYST

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Coffinite

U(SiO4)1-x(OH)4x
Dana No: 51.05.02.04 Strunz No: 09.AD.30
Locality:

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