Thornasite Mineral Data

General Thornasite Information

Chemical Formula:

Na12Th3[Si8O19]4•18(H2O)

Composition:

Molecular Weight = 3,410.96 gm

Sodium 8.09 % Na 10.90 % Na₂O

Thorium 20.41 % Th 23.22 % ThO₂

Silicon 26.35 % Si 56.37 % SiO₂

Hydrogen 1.06 % H 9.51 % H₂O

Oxygen 44.09 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Na₁₂Th₃(Si8O19)₄•18(H₂O)

IMA Status:

Approved IMA 1987

Locality:

DeMix quarry, Mt. St. Hilaire, Quebec, Canada. Link to MinDat.org Location Data.

Name Origin:

Named for its composition (Thorium, Na, Si).

Name Pronunciation:

Thornasite + Pronunciation

Synonym:

ICSD 89792

IMA1985-050

PDF 40-506

Thornasite Image

Images:

Thornasite

Comments: Opaque thornasite microcrystals.
Location: DeMix-Varennes Quarry, Saint Amable Sill, Varennes, Quebec, Canada. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Thornasite Crystallography

Axial Ratios:

a:c = 1:0.59264

Cell Dimensions:

a = 29.124, c = 17.2602, Z = 6; V = 12,678.81 Den(Calc)= 2.68

Crystal System:

Trigonal - Hexagonal Scalenohedral H-M Symbol (3 2/m) Space Group: R 3c

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

By Intensity(I/I_o): 7.27(1), 4.17(0.7), 8.17(0.3),

Physical Properties of Thornasite

Cleavage:

None

Color:

Colorless, Pale green.

Density:

2.62

Diaphaneity:

Transparent to Translucent

Habit:

Anhedral Grains - Granular minerals without the expression of crystal shapes

Habit:

Metamict - Mineral originally crystalline, now amorphous due to radiation damage.

Habit:

Microscopic Crystals - Crystals visible only with microscopes.

Luminescence:

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

Luster:

Vitreous - Waxy

Streak:

white

Optical Properties of Thornasite

Dichroism (e):

colorless.

Dichroism (w):

colorless.

Gladstone-Dale:

CI meas= 0.067 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= 0.088 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1907,KPDmeas= 0.195,KC= 0.2091
Ncalc = 1.55 - 1.56

Optical Data:

Uniaxial (+), w=1.51, e=1.512, bire=0.0020.

Calculated Properties of Thornasite

Electron Density:

Bulk Density (Electron Density)=2.52 gm/cc
note: Specific Gravity of Thornasite =2.62 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Thornasite= 448.19 barns/electron
U=PE_Thornasite x r_electron=1,127.79 barns/cc.

Radioactivity:

GRapi = 418,148.63 (Gamma Ray American Petroleum Institute Units)
Concentration of Thornasite per GRapi unit = 2.39 (PPM)

Thornasite 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) 72.74 ± 18.19 grams of pure Thornasite .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 7274.1 ±1818.5 grams of pure Thornasite .

**Estimated Radioactivity from Thornasite** - 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 / 9.00 cm	9,142,865	2.47E-04	418,148.63	137.47
100 gm / 4.18 cm	914,287	2.47E-05	41,814.86	13.75
10 gm / 1.94 cm	91,429	2.47E-06	4,181.49	1.37
1 gm / 9.00 mm	9,143	2.47E-07	418.15	0.14
0.1 gm / 4.18 mm	914	2.47E-08	41.81	0.01
0.01 gm / 1.94 mm	91	2.47E-09	4.18	0.00
0.001 gm / 0.90 mm	9	2.47E-10	0.42	0.00

Weight of pure Thornasite in grams (gm) and Calculated Diameter of a Sphere with a Density of 2.62 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

Thornasite Classification

Dana Class:

72.01.02.01 (72)Phyllosilicate Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings

(72.01)with 4-membered rings

(72.01.02)Dana Group

72.01.02.01 Thornasite Na12Th3[Si8O19]4•18(H2O) R 3c 3 2/m

Strunz Class:

09.GF.50 09 - SILICATES (Germanates)

09.G - Tektosilicates with Zeolitic H2O

09.GF -Other Rare Zeolites

09.GF.50 Thornasite Na12Th3[Si8O19]4•18(H2O) R 3c 3 2/m

Other Thornasite Information

References:

NAME( Dana8) PHYS. PROP.(AmMin, vol 85, p 1521;Dana8) OPTIC PROP.(Am.Min.,Vol.73,p931,1988)

See Also:

Links to other databases for Thornasite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Athena
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - GeoScienceWorld
8 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - Handbook of Mineralogy (UofA)
12 - MinDAT
13 - Mineralienatlas (Deutsch)
14 - Online Mineral Museum
15 - QUT Mineral Atlas
16 - Ruff.Info
17 - Uranium Minerals

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Print or Cut-and-Paste your Thornasite Specimen Label here :

Thornasite

Na12Th3[Si8O19]4•18(H2O)
Dana No: 72.01.02.01 Strunz No: 09.GF.50
Locality:

Notes:

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