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Thornasite

A valid IMA mineral species

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Thornasite

Aris Quarries, Aris, Windhoek Rural, Khomas Region, Namibia

Thornasite, etc.

Aris Quarries, Aris, Windhoek Rural, Khomas Region, Namibia

Thornasite, etc.

Aris Quarries, Aris, Windhoek Rural, Khomas Region, Namibia

Thornasite

Aris Quarries, Aris, Windhoek Rural, Khomas Region, Namibia

Thornasite, etc.

Aris Quarries, Aris, Windhoek Rural, Khomas Region, Namibia

Thornasite, etc.

Aris Quarries, Aris, Windhoek Rural, Khomas Region, Namibia

Thornasite

Aris Quarries, Aris, Windhoek Rural, Khomas Region, Namibia

Thornasite, etc.

Aris Quarries, Aris, Windhoek Rural, Khomas Region, Namibia

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About ThornasiteHide

Formula:

Na₁₂Th⁴⁺₃(Si₈O₁₉)₄ · 18H₂O

Originally given as (Na,K)ThSi₁₁(O,F,OH)₂₅.8H₂O.

Colour:

Light green to beige

Lustre:

Vitreous, Waxy, Greasy, Pearly

Specific Gravity:

2.62

Crystal System:

Trigonal

Member of:

Zeolite Group

Name:

The name reflects its composition: thorium (Thor), sodium (Na) and silicon (Si).

Type Locality:

ⓘ Poudrette quarry (De-Mix quarry; Demix quarry; Uni-Mix quarry; Carrière Mont Saint-Hilaire; MSH), Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada

This page provides mineralogical data about Thornasite.

Unique IdentifiersHide

Mindat ID:

3947

Long-form identifier:

mindat:1:1:3947:1

IMA Classification of ThornasiteHide

IMA status:

Approved

IMA Formula:

Na₁₂Th⁴⁺₃(Si₈O₁₉)₄·18H₂O

Approval year:

1985

First published:

1987

Classification of ThornasiteHide

Strunz-mindat (2026):

9.00.50

9 : SILICATES (Germanates)
0 :
0 :

Dana 8th ed.:

72.1.2.1

72 : PHYLLOSILICATES Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
1 : Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings with 4-membered rings

Hey's CIM Ref.:

14.11.4

14 : Silicates not Containing Aluminum
11 : Silicates of Th and Hg

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Symbol	Source	Reference for Standard
Tna	IMA–CNMNC	Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Physical Properties of ThornasiteHide

Lustre:

Vitreous, Waxy, Greasy, Pearly

Transparency:

Transparent, Translucent, Opaque

Colour:

Light green to beige

Streak:

White

Hardness Data:

Could not be measured

Comment:

Could not be measured due to the small crystal size and brittleness.

Tenacity:

Brittle

Fracture:

Irregular/Uneven, Sub-Conchoidal

Density:

2.62(2) g/cm³ (Measured) 2.627 g/cm³ (Calculated)

Optical Data of ThornasiteHide

Type:

Uniaxial (+)

RI values:

n_ω = 1.510(1) n_ε = 1.512(1)

Max. Birefringence:

δ = 0.002
Based on recorded range of RI values above.

Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.

Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.

Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.

Thickness: 30 µm Order divisions

Rotation:

Surface Relief:

Low (negative)
Relative to Canada balsam mounting medium (n ≈ 1.537).

This shows the grain boundary and Becke line effect under plane-polarised light, based on the contrast between this mineral's average refractive index and the mounting medium. It does not take into account mineral colouration.

Focus:

In focus

Interference Figure:

This shows the idealized uniaxial interference figure - the conoscopic (convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis centred and vertical. The coloured rings are isochromatics, computed with the same physics as the Michel-Lévy bar above; the dark cross is the isogyre.

For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.

Thickness: 30 µm

Chemistry of ThornasiteHide

Mindat Formula:

Na₁₂Th⁴⁺₃(Si₈O₁₉)₄ · 18H₂O

Originally given as (Na,K)ThSi₁₁(O,F,OH)₂₅.8H₂O.

Element Weights:

Element	% weight
O	44.092 %
Si	26.349 %
Th	20.408 %
Na	8.088 %
H	1.064 %

Calculated from ideal end-member formula.

Elements listed:

H, Na, O, Si, Th - search for minerals with similar chemistry

Common Impurities:

U,Al,Ca,Cl

Crystallography of ThornasiteHide

Crystal System:

Trigonal

Class (H-M):

3m - Ditrigonal Pyramidal

Space Group:

R3m

Setting:

R3m

Cell Parameters:

a = 29.08 Å, c = 17.30 Å

Ratio:

a:c = 1 : 0.595

Unit Cell V:

12,669.68 Å³ (Calculated from Unit Cell)

Crystal StructureHide

Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4

View
CIF File Best | x | y | z | a | b | c

Rotation
Stop | Start

Labels
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure

ID	Species	Reference	Link	Year	Locality	Pressure (GPa)	Temp (K)
0002591	Thornasite	Li Y, Krivovichev S V, Burns P C (2000) The crystal structure of thornasite: A novel interrupted silicate framework American Mineralogist 85 1521-1525		2000		0	293

CIF Raw Data - click here to close

data_global
_chemical_name_mineral 'Thornasite'
loop_
_publ_author_name
'Li Y'
'Krivovichev S V'
'Burns P C'
_journal_name_full 'American Mineralogist'
_journal_volume 85 
_journal_year 2000
_journal_page_first 1521
_journal_page_last 1525
_publ_section_title
;
 The crystal structure of thornasite: A novel interrupted silicate framework
;
_database_code_amcsd 0002591
_chemical_formula_sum 'Th3 Si32 Na12 O94 H36'
_cell_length_a 29.124
_cell_length_b 29.124
_cell_length_c 17.2602
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 12678.810
_exptl_crystal_density_diffrn      2.680
_symmetry_space_group_name_H-M 'R -3 c'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '2/3+x,1/3+y,1/3+z'
  '1/3+x,2/3+y,2/3+z'
  'x,x-y,1/2+z'
  '2/3+x,1/3+x-y,5/6+z'
  '1/3+x,2/3+x-y,1/6+z'
  'y,x,1/2-z'
  '2/3+y,1/3+x,5/6-z'
  '1/3+y,2/3+x,1/6-z'
  '-x+y,y,1/2+z'
  '2/3-x+y,1/3+y,5/6+z'
  '1/3-x+y,2/3+y,1/6+z'
  '-x,-x+y,1/2-z'
  '2/3-x,1/3-x+y,5/6-z'
  '1/3-x,2/3-x+y,1/6-z'
  '-y,-x,1/2+z'
  '2/3-y,1/3-x,5/6+z'
  '1/3-y,2/3-x,1/6+z'
  'x-y,-y,1/2-z'
  '2/3+x-y,1/3-y,5/6-z'
  '1/3+x-y,2/3-y,1/6-z'
  'y,-x+y,-z'
  '2/3+y,1/3-x+y,1/3-z'
  '1/3+y,2/3-x+y,2/3-z'
  '-x+y,-x,z'
  '2/3-x+y,1/3-x,1/3+z'
  '1/3-x+y,2/3-x,2/3+z'
  '-x,-y,-z'
  '2/3-x,1/3-y,1/3-z'
  '1/3-x,2/3-y,2/3-z'
  '-y,x-y,z'
  '2/3-y,1/3+x-y,1/3+z'
  '1/3-y,2/3+x-y,2/3+z'
  'x-y,x,-z'
  '2/3+x-y,1/3+x,1/3-z'
  '1/3+x-y,2/3+x,2/3-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Th   0.15425   0.82091   0.08333
Si1   0.16840   0.90080  -0.08610
Si2   0.06410   0.80730  -0.06890
Si3   0.15950   0.94990   0.05980
Si4   0.09910   0.72890  -0.09290
Si5   0.06450   0.96630   0.05120
Si6   0.00000   0.00000   0.34150
Na1   0.14860   0.89540   0.24130
Na2   0.02870   0.82370   0.11840
O1   0.19250   0.87130  -0.03900
O2   0.16290   0.90540   0.10740
O3   0.13620   0.75480  -0.01950
O4   0.07690   0.81090   0.02040
O5   0.00820   0.80330  -0.08850
O6   0.05870   0.66667  -0.08333
O7   0.06280   0.75630  -0.10990
O8   0.10860   0.85920  -0.11500
O9   0.16580   0.94650  -0.03460
O10   0.19980   0.93130  -0.16280
O11   0.10330   0.94660   0.07620
O12   0.09600   0.01590  -0.00670
O13   0.00000   0.00000   0.25000
O14   0.04320   0.98220   0.12540
Wat15   0.23230   0.00000   0.25000
Wat16   0.09980   0.94220   0.26680
Wat17   0.00000   0.89100   0.25000
Wat18   0.30720   0.04210   0.34080
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Th 0.01700 0.01700 0.01400 0.00900 -0.00100 0.00100
Si1 0.01600 0.02000 0.01200 0.00700 0.00100 0.00500
Si2 0.01400 0.01900 0.01700 0.00800 -0.00200 -0.00100
Si3 0.01600 0.01300 0.01700 0.00700 0.00000 0.00200
Si4 0.01700 0.01200 0.01300 0.00600 -0.00100 0.00100
Si5 0.03600 0.03900 0.06000 0.02200 0.00000 -0.00300
Si6 0.03900 0.03900 0.07900 0.02000 0.00000 0.00000
Na1 0.11400 0.07600 0.03000 0.06500 0.00800 0.00300
Na2 0.06000 0.14100 0.05300 0.05900 -0.00400 0.00900
O1 0.02700 0.02800 0.01900 0.01700 0.00700 0.01000
O2 0.04500 0.01600 0.01700 0.01700 -0.00400 0.00000
O3 0.03100 0.02500 0.02300 0.01600 -0.01600 -0.00800
O4 0.01900 0.03800 0.01500 0.01600 -0.00200 -0.00400
O5 0.01800 0.05400 0.01700 0.01900 0.00100 -0.00100
O6 0.02200 0.01100 0.04100 0.00600 0.00600 0.01100
O7 0.02900 0.02100 0.02200 0.01700 -0.00700 -0.00500
O8 0.01700 0.01900 0.02400 0.00300 -0.00400 0.00500
O9 0.03000 0.01700 0.01500 0.01000 -0.00100 0.00100
O10 0.02900 0.04000 0.01800 0.01800 0.01300 0.01700
O11 0.02800 0.06500 0.04600 0.03400 0.00200 0.01000
O12 0.06600 0.04900 0.08900 0.02200 0.00800 0.02300
O14 0.05300 0.08300 0.08400 0.04300 0.01100 -0.00900
Wat15 0.21000 0.21000 0.04000 0.10700 0.01200 0.02300
Wat16 0.21000 0.17000 0.13000 0.09000 -0.02500 0.02900
Wat17 0.37000 0.37000 0.38000 0.18700 -0.00300 -0.00200
Wat18 0.15500 0.08000 0.12100 0.05100 0.05800 -0.00900

X-Ray Powder DiffractionHide

Powder Diffraction Data:

d-spacing	Intensity
14.54 Å	(20)
8.17 Å	(30)
7.27 Å	(100)
5.09 Å	(20)
4.17 Å	(70)
3.239 Å	(30)
2.890 Å	(25)

Geological EnvironmentHide

Paragenetic Mode(s):

Paragenetic Mode	Earliest Age (Ga)
Stage 4b: Highly evolved igneous rocks	>3.0
35 : Ultra-alkali and agpaitic igneous rocks

Type Occurrence of ThornasiteHide

Type Locality:

ⓘ Poudrette quarry (De-Mix quarry; Demix quarry; Uni-Mix quarry; Carrière Mont Saint-Hilaire; MSH), Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada

General Appearance of Type Material:

Anhedral crystals to 0.7 mm, embedded in patches of brockite.

Place of Conservation of Type Material:

Canadian Museum of Nature, Ottawa, Ontario, Canada, number 50770 (holotype).
Royal Ontario Museum, Toronto, Ontario, Canada, number M42070 (cotype).

Associated Minerals at Type Locality:

Analcime

Brockite

Yofortierite

Synonyms of ThornasiteHide

IMA1985-050

Other Language Names for ThornasiteHide

Dutch:Thornasiet

German:Thornasit

Russian:Торнасит

Spanish:Thornasita

Relationship of Thornasite to other SpeciesHide

Member of:

Zeolite Group

Other Members of Zeolite Group:

Alflarsenite	NaCa₂Be₃Si₄O₁₃(OH) · 2H₂O	Mon. 2 : P2₁
Amicite	K₂Na₂Al₄Si₄O₁₆ · 5H₂O	Mon. 2
Ammonioleucite	(NH₄)(AlSi₂O₆)	Tet. 4/m : I4₁/a
Analcime	Na(AlSi₂O₆) · H₂O	Tric. 1 : P1
Arzamastsevite	K₆Al₅Si₆O₂₀(OH)₄Cl	Tet. 42m : I42m
Bellbergite	(K,Ba,Sr)₂Sr₂Ca₂(Ca,Na)₄[Al₃Si₃O₁₂]₆ · 30H₂O	Hex.
Bikitaite	LiAlSi₂O₆ · H₂O	Tric. 1 : P1
Boggsite	Ca₈Na₃(Si,Al)₉₆O₁₉₂ · 70H₂O	Orth. mmm(2/m2/m2/m) : Imma
Brewsterite Subgroup	Zeolite Group.
Chabazite-Levyne Subgroup	M[Al₂Si₄O₁₂] · 6H₂O
Chiavennite	CaMnBe₂Si₅O₁₃(OH)₂ · 2H₂O	Mon. 2/m : P2₁/b
Clinoptilolite Subgroup	(Na/Ca/K)_3-6[Al_6-7Si_29-30O₇₂] · 20H₂O
Cowlesite	CaAl₂Si₃O₁₀ · 6H₂O	Orth. mmm(2/m2/m2/m)
Dachiardite Subgroup	Zeolite Group.
Direnzoite	NaK₆MgCa₂(Al₁₃Si₄₇O₁₂₀) · 36H₂O	Orth. mmm(2/m2/m2/m) : Pmmn
Edingtonite	Ba[Al₂Si₃O₁₀] · 4H₂O	Orth. 222 : P2₁2₁2₁
Epistilbite	CaAl₂Si₆O₁₆ · 5H₂O	Mon.
Erionite Subgroup	M₂[Al₄Si₁₄O₃₆] · 15H₂O
Fabrièsite	Na₃Al₃Si₃O₁₂ · 2H₂O	Orth. mm2 : Pmm2
Faujasite Subgroup	M_3.5[Al₇Si₁₇O₄₈] · 32H₂O
Ferrierite Subgroup	Name used for unanalysed specimens that could be either ferrierite-K, ferrierite-Mg, ...
Ferrochiavennite	Ca_1-2Fe[(Si,Al,Be)₅Be₂O₁₃(OH)₂] · 2H₂O	Mon. 2/m : P2₁/b
Flörkeite	(K₃Ca₂Na)[Al₈Si₈O₃₂] · 12H₂O	Tric. 1 : P1
Garronite Subgroup
Gaultite	Na₄Zn₂Si₇O₁₈ · 5H₂O	Orth. mm2 : Fdd2
Gismondine Subgroup	Zeolite Group.
Gmelinite Subgroup	In 1997, gmelinite was split into Gmelinite-Ca, Gmelinite-Na and Gmelinite-K.
Gobbinsite	Na₅(Si₁₁Al₅)O₃₂ · 11H₂O	Orth. mmm(2/m2/m2/m) : Pnma
Goosecreekite	Ca[Al₂Si₆O₁₆] · 5H₂O	Mon. 2 : P2₁
Gottardiite	Na₃Mg₃Ca₅Al₁₉Si₁₁₇O₂₇₂ · 93H₂O	Orth. mmm(2/m2/m2/m) : Cmca
Heulandite Subgroup	(Na/Ca/K)_5-6[Al_8-9 Si_27-28 O₇₂] · nH₂O
Hsianghualite	Ca₃Li₂(Be₃Si₃O₁₂)F₂	Iso. 23 : I2₁3
Kalborsite	K₆Al₄BSi₆O₂₀(OH)₄Cl	Tet. 42m : P42₁c
Kirchhoffite	Cs(BSi₂O₆)	Tet. 4/mmm(4/m2/m2/m) : I4₁/acd
Laumontite	CaAl₂Si₄O₁₂ · 4H₂O	Mon. 2/m : B2/m
Leucite	K(AlSi₂O₆)	Tet. 4/m : I4₁/a
Limousinite	BaCa[Be₄P₄O₁₆] · 6H₂O	Mon. 2/m : P2₁/b
Lithosite	K₆Al₄Si₈O₂₅ · 2H₂O	Mon.
Loomisite	Ba[Be₂P₂O₈] · H₂O	Mon. m
Lovdarite	K₂Na₆Be₄Si₁₄O₃₆ · 9H₂O	Orth. mm2
Maricopaite	Pb₇Ca₂(Si,Al)₄₈O₁₀₀ · 32H₂O	Orth.
Martinandresite	Ba₂(Al₄Si₁₂O₃₂) · 10H₂O	Orth. mmm(2/m2/m2/m) : Pmmn
Mazzite Subgroup	Zeolite Group.
Meierite	Ba₄₄Si₆₆Al₃₀O₁₉₂Cl₂₅(OH)₃₃	Iso. m3m(4/m32/m) : Im3m
Merlinoite	K₅Ca₂(Si₂₃Al₉)O₆₄ · 24H₂O	Orth. mmm(2/m2/m2/m) : Immm
Montesommaite	(K,Na)₉Al₉Si₂₃O₆₄ · 10H₂O	Orth. mm2 : Fdd2
Mordenite	(Na₂,Ca,K₂)₄(Al₈Si₄₀)O₉₆ · 28H₂O	Orth.
Mountainite	KNa₂Ca₂[Si₈O₁₉(OH)] · 6H₂O	Mon. 2/m : P2/b
Mutinaite	Na₃Ca₄Si₈₅Al₁₁O₁₉₂ · 60H₂O	Orth. mmm(2/m2/m2/m) : Pnma
Nabesite	Na₂BeSi₄O₁₀ · 4H₂O	Orth. 222 : P2₁2₁2₁
Natrolite Subgroup	A subgroup of the Zeolite Group.
Offretite	KCaMg(Si₁₃Al₅)O₃₆ · 15H₂O	Hex. 6m2 : P6m2
Pahasapaite	Li₈(Ca,Li,K)_10.5Be₂₄(PO₄)₂₄ · 38H₂O	Iso. 23 : I23
Parthéite	Ca₂(Si₄Al₄) O₁₅ (OH)₂ · 4H₂O	Mon. 2/m : B2/b
Paulingite Subgroup	Paulingite was originally described in 1960.
Perlialite	K₉Na(Ca,Sr)[Al₂Si₄O₁₂]₆ · 15H₂O	Hex. 6/mmm(6/m2/m2/m) : P6/mmm
Phillipsite Subgroup	(Ca_0.5,K,Na,Ba_0.5)_4-7[Al_4-7Si_12-9O₃₂] ^. 12H₂O
Pollucite	(Cs,Na)₂(Al₂Si₄O₁₂) · 2H₂O	Iso. m3m(4/m32/m) : Ia3d
Roggianite	Ca₂Be(OH)₂Al₂Si₄O₁₃ · 2.5H₂O	Tet. 4/mmm(4/m2/m2/m) : I4/mcm
Rongibbsite	Pb₂(Si₄Al)O₁₁(OH)	Mon. 2/m : B2/m
Stilbite Subgroup	M_6-7[Al_8-9Si_27-28O₇₂] · nH₂O
Terranovaite	(Na,Ca)₈(Si₆₈Al₁₂)O₁₆₀ · 29H₂O	Orth.
Thomsonite Subgroup	The large majority of "thomsonite" is thomsonite-Ca.
Tschernichite	(Ca,Na₂)[Al₂Si₄O₁₂] · 4-8H₂O	Tet. 4/mmm(4/m2/m2/m) : P4/mmm
Tschörtnerite	Ca₄(Ca,Sr,K,Ba)₃Cu₃[Al₃Si₃O₁₂]₄(OH)₈ · nH₂O	Iso. m3m(4/m32/m) : Fm3m
'UM1996-38-SiO:AlCaHNa'	Na-Ca-Al-Si-O-H
'UM1999-33-SiO:AlHKNa'	K₇Na₅Al₁₂Si₂₀O₆₄ · 24H₂O
'UM2002-40-SiO:AlCaHKMgNa'	(Mg,Ca,Na,K)_7.5(Al_12.8Si_51.2)O₁₂₈ · 65H₂O	Tet. 422 : P4₁22
'Unnamed (Ca analogue of Merlinoite)'	(Ca,K,Na)₅(Ca,Ba)₂Al₉Si₂₃O₆₄ · 23H₂O ?
Wairakite	Ca(Al₂Si₄O₁₂) · 2H₂O	Mon. 2/m : B2/m
Weinebeneite	CaBe₃(PO₄)₂(OH)₂ · 4H₂O	Mon. m : Bb
Wenkite	(Ba,K)₄(Ca,Na)₆[(Si,Al)₂₀O₃₉(OH)₂](SO₄)₃ · 0.5H₂O	Hex. 6m2 : P62m
Wilancookite	(Ba₅Li₂◻)Ba₆Be₂₄P₂₄O₉₆ · 26H₂O	Iso. 23 : I23
Willhendersonite	KCa[Al₃Si₃O₁₂] · 5H₂O	Tric. 1 : P1
Yugawaralite	CaAl₂Si₆O₁₆ · 4H₂O	Mon. m : Pb

Common AssociatesHide

Associations Based on Photo Data:

4 photos of Thornasite associated with Aegirine	NaFe³⁺Si₂O₆
4 photos of Thornasite associated with Villiaumite	NaF
3 photos of Thornasite associated with Natrolite	Na₂Al₂Si₃O₁₀ · 2H₂O
3 photos of Thornasite associated with Tuperssuatsiaite	Fe³⁺Fe³⁺₂(Na◻)◻₂Si₈O₂₀(OH)₂(H₂O)₄ · 2H₂O
2 photos of Thornasite associated with Ellingsenite	Na₅Ca₆Si₁₈O₃₈(OH)₁₃ · 6H₂O

Related Minerals - Strunz-mindat Grouping Hide

9.00.	Clino-ferri-holmquistite	◻Li₂(Mg₃Fe³⁺₂)(Si₈O₂₂)(OH)₂	Mon. 2/m : B2/m
9.00.	Mendigite	Mn₂Mn₂MnCa(Si₃O₉)₂	Tric. 1 : P1
9.00.	Alflarsenite	NaCa₂Be₃Si₄O₁₃(OH) · 2H₂O	Mon. 2 : P2₁
9.00.	Bridgmanite Subgroup	ABSiO₃
9.00.	Ferroericssonite	BaFe²⁺₂ Fe³⁺(Si₂O₇)O(OH)	Mon. 2/m : B2/m
9.00.	Zvyaginite	NaZnNb₂Ti[Si₂O₇]₂(OH,F)₃(H₂O)_4+x (x < 1)	Tric. 1 : P1
9.00.	Burnettite	CaVAlSiO₆	Mon. 2/m : B2/b
9.00.	Ferrisepiolite	(Fe³⁺,Fe²⁺,Mg)₄((Si,Fe³⁺)₆O₁₅)(O,OH)₂ · 6H₂O	Orth. mmm(2/m2/m2/m)
9.00.	Yegorovite	Na₄[Si₄O₈(OH)₄] · 7H₂O	Mon. 2/m : P2₁/b
9.00.	Chrysotile	Mg₃(Si₂O₅)(OH)₄	Mon. m : Bb
9.00.	'Shkatulkalita'
9.00.15 va	'Chromoamesite'	Mg₂(Al,Cr)(AlSiO₅)(OH)₄

RadioactivityHide

Radioactivity:

Element	% Content	Activity (Bq/kg)	Radiation Type
Uranium (U)	0.0000%	0	α, β, γ
Thorium (Th)	20.4082%	816,328	α, β, γ
Potassium (K)	0.0000%	0	β, γ

For comparison:

Banana: ~15 Bq per fruit
Granite: 1,000–3,000 Bq/kg
EU exemption limit: 10,000 Bq/kg

Note: Risk is shown relative to daily recommended maximum exposure to non-background radiation of 1000 µSv/year. Note that natural background radiation averages around 2400 µSv/year so in reality these risks are probably extremely overstated! With infrequent handling and safe storage natural radioactive minerals do not usually pose much risk.

Interactive Simulator:

Note: The mass selector refers to the mass of radioactive mineral present, not the full specimen, also be aware that the matrix may also be radioactive, possibly more radioactive than this mineral!

Mass of radioactive mineral:

Shielding material:

Activity: –

Distance	Dose rate	Risk
1 cm
10 cm
1 m

The external dose rate (D) from a radioactive mineral is estimated by summing the gamma radiation contributions from its Uranium, Thorium, and Potassium content, disregarding daughter-product which may have a significant effect in some cases (eg 'pitchblende'). This involves multiplying the activity (A, in Bq) of each element by its specific gamma ray constant (Γ), which accounts for its unique gamma emissions. The total unshielded dose at 1 cm is then scaled by the square of the distance (r, in cm) and multiplied by a shielding factor (μ_shield). This calculation provides a 'worst-case' or 'maximum risk' estimate because it assumes the sample is a point source and entirely neglects any self-shielding where radiation is absorbed within the mineral itself, meaning actual doses will typically be lower. The resulting dose rate (D) is expressed in microsieverts per hour (μSv/h).

D = ((A_U × Γ_U) + (A_Th × Γ_Th) + (A_K × Γ_K)) / r² × μ_shield

Fluorescence of ThornasiteHide

In UV light:

Bright apple-green under long- and short-wave ultraviolet light.

Other InformationHide

Thermal Behaviour:

Heating at 300°C results in complete collapse of the structure.

Notes:

Slightly metamict.

Slightly attacked by 1:1 HCl at room temperature. Unaffected by either 1:1 HNO3 or H2SO4.

Health Risks:

No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

Internet Links for ThornasiteHide

mindat.org URL:

https://www.mindat.org/min-3947.html
Please feel free to link to this page.

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External Links:

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Raman and XRD data at RRUFF project

References and PDF downloads at RRUFF project

American Mineralogist Crystal Structure Database

Handbook of Mineralogy page PDF

Mineral Dealers:

Buy from D. Joyce minerals

References for ThornasiteHide

Reference List:

Ansell, V. E.; Chao, George Y. (1987) Thornasite, a new hydrous sodium thorium silicate from Mont St-Hilaire, Quebec. The Canadian Mineralogist, 25. p.181-183.

Horváth, László, Gault, Robert A., Tarassoff, Peter, Pfenninger-Horváth, Elsa (1998) Mineralogy of the Saint-Amable Sill, Varennes and Saint-Amable, Quebec. The Mineralogical Record, 29 (2) 83-118

Krivovichev, Sergey V., Burns, Peter C., Li, Yaping, Krivovichev, Sergey V., Burns, Peter C. (2000) The crystal structure of thornasite, Na₁₂Th₃[Si₈O₁₉]₄(H₂O)₁₈: A novel interrupted silicate framework. American Mineralogist, 85 (10) 1521-1525 doi:10.2138/am-2000-1025

LI, Y., KRIVOVICHEV, V., BURNS, P.C. (2001) Errata. American Mineralogist, 86, 384.

(2001) Thornasite. Handbook of Mineralogy. Mineralogical Society of America

Localities for ThornasiteHide

Showing 4 localities.

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the

symbol to view information about a locality. The

symbol next to localities in the list can be used to jump to that position on the map.

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Locality ListHide

- This locality has map coordinates listed.

- This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality.

- Good crystals or important locality for species.

- World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). ~~Struck out~~ - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.


Canada (TL)
Québec Montérégie La Vallée-du-Richelieu RCM Mont Saint-Hilaire ⓘ Poudrette quarry (De-Mix quarry; Demix quarry; Uni-Mix quarry; Carrière Mont Saint-Hilaire; MSH) (TL)	Ansell et al. (1987) +4 other references
Lajemmerais RCM Varennes & St-Amable ⓘ Saint-Amable sill	Horváth et al. (1998)
ⓘ Demix-Varennes quarry	Horváth et al. (1998)

Namibia
Khomas Region Windhoek Rural Aris ⓘ Aris Quarries	Paula Piilonen +3 other references

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Thornasite

About ThornasiteHide

Unique IdentifiersHide

IMA Classification of ThornasiteHide

Classification of ThornasiteHide

Mineral SymbolsHide

Physical Properties of ThornasiteHide

Optical Data of ThornasiteHide

Chemistry of ThornasiteHide

Crystallography of ThornasiteHide

Crystal StructureHide

X-Ray Powder DiffractionHide

Geological EnvironmentHide

Type Occurrence of ThornasiteHide

Synonyms of ThornasiteHide

Other Language Names for ThornasiteHide

Relationship of Thornasite to other SpeciesHide

Common AssociatesHide

Related Minerals - Strunz-mindat GroupingHide

RadioactivityHide

Fluorescence of ThornasiteHide

Other InformationHide

Internet Links for ThornasiteHide

References for ThornasiteHide

Localities for ThornasiteHide

Locality ListHide

Related Minerals - Strunz-mindat Grouping Hide