Boltwoodite
A valid IMA mineral species - grandfathered
This page is currently not sponsored. Click here to sponsor this page.
About Boltwoodite
Bertram Borden Boltwood
Formula:
(K,Na)(UO2)(SiO3OH) · 1.5H2O
Colour:
Pale yellow, orange yellow
Lustre:
Sub-Vitreous, Waxy, Silky
Hardness:
3½ - 4
Specific Gravity:
4.7
Crystal System:
Monoclinic
Member of:
Name:
For Bertram Borden Boltwood (1870-1927), radiochemist at Yale University, New Haven, Connecticut, USA. Named by Clifford Frondel and Jun Ito.
Isostructural with:
Unique Identifiers
Mindat ID:
716
Long-form identifier:
mindat:1:1:716:0
GUID
(UUID V4):
(UUID V4):
cb9b4706-f13e-4703-be4a-c83143a8513b
IMA Classification of Boltwoodite
Approved, 'Grandfathered' (first described prior to 1959)
First published:
1956
Type description reference:
Classification of Boltwoodite
9.AK.15
9 : SILICATES (Germanates)
A : Nesosilicates
K : Uranyl neso- and polysilicates
9 : SILICATES (Germanates)
A : Nesosilicates
K : Uranyl neso- and polysilicates
53.3.1.5
53 : NESOSILICATES Insular SiO4 Groups and Other Anions or Complex Cations
3 : Insular SiO4 Groups and Other Anions of Complex Cations with (UO2)
53 : NESOSILICATES Insular SiO4 Groups and Other Anions or Complex Cations
3 : Insular SiO4 Groups and Other Anions of Complex Cations with (UO2)
14.16.6
14 : Silicates not Containing Aluminum
16 : Silicates of U
14 : Silicates not Containing Aluminum
16 : Silicates of U
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference |
|---|---|---|
| Bwd | 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 Boltwoodite
Sub-Vitreous, Waxy, Silky
Transparency:
Translucent
Comment:
Aggregates vitreous to silky, dull to earthy in pseudomorphs
Colour:
Pale yellow, orange yellow
Streak:
White
Hardness:
3½ - 4 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Perfect on {010}, imperfect on {001}.
Perfect on {010}, imperfect on {001}.
Fracture:
Irregular/Uneven
Density:
4.7 g/cm3 (Measured) 4.46 g/cm3 (Calculated)
Optical Data of Boltwoodite
Type:
Biaxial (-)
RI values:
nα = 1.668 - 1.670 nβ = 1.695 - 1.696 nγ = 1.698 - 1.703
Birefringence:
0.007-0.008
Max Birefringence:
δ = 0.030 - 0.033
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
High
Dispersion:
r > v or r < v
Pleochroism:
Weak
Comments:
X = colorless; Y = Z = yellow.
Chemistry of Boltwoodite
Mindat Formula:
(K,Na)(UO2)(SiO3OH) · 1.5H2O
Common Impurities:
Fe,Ca,Na
Crystallography of Boltwoodite
Crystal System:
Monoclinic
Class (H-M):
2 - Sphenoidal
Space Group:
P21
Cell Parameters:
a = 7.073(2) Å, b = 7.064(1) Å, c = 6.638(1) Å
β = 105.45°
β = 105.45°
Ratio:
a:b:c = 1.001 : 1 : 0.94
Unit Cell V:
319.67 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Radiating acicular to fibrous crystals, also earthy pseudomorphs of uranium minerals.
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
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) |
|---|---|---|---|---|---|---|---|
| 0000838 | Boltwoodite | Stohl F V, Smith D K (1981) The crystal chemistry of the uranyl silicate minerals American Mineralogist 66 610-625 |  | 1981 | New Method mine, Amboy, California, USA | 0 | 293 |
| 0005562 | Boltwoodite | Burns P C (1998) The structure of boltwoodite and implications of solid solution toward sodium boltwoodite The Canadian Mineralogist 36 1069-1075 | | 1998 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.81 Å | (10) |
| 6.40 Å | (50) |
| 3.54 Å | (70) |
| 3.40 Å | (90) |
| 2.95 Å | (80) |
| 2.91 Å | (70) |
| 1.900 Å | (60) |
| 1.764 Å | (60) |
Comments:
35-490
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47f : [Uranyl (U⁶⁺) minerals] |
Geological Setting:
Alteration zone around uranium deposits.
Type Occurrence of Boltwoodite
General Appearance of Type Material:
Wart-like aggregates of fibers coating fractures in sandstone.
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, 112710.
Geological Setting of Type Material:
An oxidation product of primary black U ores.
Associated Minerals at Type Locality:
Reference:
Frondel, C., Ito, J. (1956) Boltwoodite, a new uranium silicate. Science: 124: 931-931.
Other Language Names for Boltwoodite
Relationship of Boltwoodite to other Species
Member of:
Other Members of this group:
| Natroboltwoodite | Na(UO2)(SiO3OH) · H2O | Orth. 2 2 2 : P21 21 21 |
| Parauranophane | Ca(UO2)2(SiO3OH)2 · 5H2O | Mon. 2/m : P21/b |
| Uranophane | Ca(UO2)2(SiO3OH)2 · 5H2O | Mon. 2 : P21 |
Common Associates
Associated Minerals Based on Photo Data:
| 74 photos of Boltwoodite associated with Calcite | CaCO3 |
| 17 photos of Boltwoodite associated with Fluorite | CaF2 |
| 10 photos of Boltwoodite associated with Uraninite | UO2 |
| 9 photos of Boltwoodite associated with Gypsum | CaSO4 · 2H2O |
| 8 photos of Boltwoodite associated with Zippeite | K3(UO2)4(SO4)2O3(OH) · 3H2O |
| 6 photos of Boltwoodite associated with Quartz | SiO2 |
| 4 photos of Boltwoodite associated with Haynesite | (UO2)3(OH)2(SeO3)2 · 5H2O |
| 3 photos of Boltwoodite associated with Brochantite | Cu4(SO4)(OH)6 |
| 3 photos of Boltwoodite associated with Malachite | Cu2(CO3)(OH)2 |
| 2 photos of Boltwoodite associated with Sklodowskite | Mg(UO2)2(SiO3OH)2 · 6H2O |
Related Minerals - Strunz-mindat Grouping
| 9.AK. | Orlite | Pb3(UO2)3(Si2O7)2 · 6H2O |
| 9.AK.05 | Soddyite | (UO2)2SiO4 · 2H2O |
| 9.AK.10 | Cuprosklodowskite | Cu(UO2)2(SiO3OH)2 · 6H2O |
| 9.AK.10 | Oursinite | Co(UO2)2(SiO3OH)2 · 6H2O |
| 9.AK.10 | Sklodowskite | Mg(UO2)2(SiO3OH)2 · 6H2O |
| 9.AK.15 | Kasolite | Pb(UO2)(SiO4) · H2O |
| 9.AK.15 | Natroboltwoodite | Na(UO2)(SiO3OH) · H2O |
| 9.AK.15 | Parauranophane | Ca(UO2)2(SiO3OH)2 · 5H2O |
| 9.AK.15 | Uranophane | Ca(UO2)2(SiO3OH)2 · 5H2O |
| 9.AK.20 | Swamboite-(Nd) | Nd0.333[(UO2)(SiO3OH)](H2O)~2.5 |
| 9.AK.25 | Haiweeite | Ca(UO2)2[Si5O12(OH)2] · 6H2O |
| 9.AK.25 | Metahaiweeite | Ca(UO2)2Si6O15 · nH2O |
| 9.AK.30 | Weeksite | K2(UO2)2(Si5O13) · 4H2O |
| 9.AK.30 | Coutinhoite | ThxBa(1-2x)(UO2)2Si5O13 · (H2O)1+y (0 < x < 0.5 and 0 < y < (2+x)) |
| 9.AK.35 | Magnioursilite | Mg4(UO2)4(Si2O5)5(OH)6 · 20H2O |
| 9.AK.35 | Calcioursilite | Ca4(UO2)4(Si2O5)5(OH)6 · 15H2O |
| 9.AK.40 | Uranosilite | UO3 · 7SiO2 |
Other Information
Health Risks:
Contains uranium - always wash hands after handling. Avoid inhaling dust when handling or breaking. Never lick or ingest. Avoid prolonged exposure in proximity of the body. Store away from inhabited areas.
Internet Links for Boltwoodite
mindat.org URL:
https://www.mindat.org/min-716.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Boltwoodite
Reference List:
Honea, Russell M. (1961) New data on boltwoodite, an alkali uranyl silicate. American Mineralogist, 46 (1-2) 12-25
Stohl, Frances V., Smith, Deane K. (1981) The crystal chemistry of the uranyl silicate minerals. American Mineralogist, 66 (5-6) 610-624
Vochten, R., Blaton, N., Peeters, O., Van Springel, K., Van Haverbeke, L. (1997) A new method of synthesis of boltwoodite and of formation of sodium boltwoodite, uranophane, sklodowskite and kasolite from boltwoodite. The Canadian Mineralogist, 35 (3) 735-741
Burns, P. C. (1998) The structure of boltwoodite and implications of solid-solution towards sodium boltwoodite. The Canadian Mineralogist, 36 (4) 1069-1075
Burns, Peter C. (2005) U6+ minerals and inorganic compounds: insights into an expanded structural hierarchy of crystal structures. The Canadian Mineralogist, 43 (6) 1839-1894 doi:10.2113/gscanmin.43.6.1839
Localities for Boltwoodite
symbol to view information about a locality.
The Locality List
- 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).
All localities listed without proper references should be considered as questionable.
Argentina | |
| Toubes |
| Honea (1961) |
| Personally collected by Günter Frenz |
| Lucero et al. (1963) |
| Lucero et al. (1963) | |
| Honea (1961) | |
Australia | |
| Brugger et al. (2003) +1 other reference |
| Honea (1961) |
Austria | |
| Blaß et al. (2000) |
Brazil | |
| Pires et al. (2014) |
Canada | |
| G.S.C. Bulletin 330. +1 other reference |
| Miller A. (1980) | |
| Trail (1980) |
| Knipping (1974) |
China | |
| Congjian Pu (1990) | |
| Hercule Shen |
| Hercule Shen |
Czech Republic | |
| Plášil et al. (2016) |
| Pauliš P. et al. (Kutna Hora, issue 1) |
| Pauliš P. et al. (Kutna Hora, issue 1) |
France | |
| - (1998) |
Germany | |
| Aufschluss 69/ (7+8) +1 other reference |
| collection H.J. Haas |
| Wittern (2001) |
Greece | |
| Michalis Fitros collection (EDS and PXRD analyses) +2 other references |
Hungary | |
| Zsombor Eva |
Iran | |
| Iranmanesh et al. (2018) |
Japan | |
| K. Watanabe (1976) |
| Watanabe (1976) |
Malawi | |
| Becker |
Mexico | |
| Wong et al. (1999, January) +1 other reference |
Namibia | |
| |
| Palfi et al. (2001) +1 other reference |
| Am.Min.: 84:993. +2 other references | |
Niger | |
| www.cnncintl.com (2015) |
Norway | |
| Eldjarn (1988) |
| Gunnar Raade (1990) +1 other reference |
Slovakia | |
| Polák Ľ. et al. (2017) |
South Africa | |
| Cairncross et al. (1995) |
Spain | |
| Joan Abella i Creus and Joan Viñals i Olià (2012) +1 other reference |
Sweden | |
| |
| |
| Natural History Museum |
| Natural History Museum | |
| |
UK | |
| Elton et al. (1995) |
| Alysson Rowan collection |
| Alysson Rowan collection |
| Tindle (2008) | |
| Handbook of Mineralogy. +1 other reference |
| Miller et al. (1966) +1 other reference | |
| R. S. W. Braithwaite and J. R. Knight (1990) |
Ukraine | |
| Cuney et al. (2012) |
| Dudar et al. (2018) | |
| Dudar et al. (2018) | |
| Cuney et al. (2012) | |
USA | |
| Bollin et al. (1958) +1 other reference |
| Daphne Ross cited in Honea (1961) +1 other reference |
| Daphne Ross cited in Honea (1961) +1 other reference | |
| Anthony et al. (1995) | |
| Austin (1964) +1 other reference | |
| Austin (1964) +1 other reference | |
| Austin (1964) +1 other reference | |
| Scarborough (1981) | |
| 108 +3 other references |
| Eckel et al. (1997) |
| Mineralogical Society of America - ... |
| Am Min 50:909-923 +1 other reference |
| Rocks & Minerals |
| Lapham & Geyer |
| American Mineralogist: 46: 12-25. +1 other reference |
| - (2005) |
| Smith (1991) | |
| - (2005) |
| Bullock (1981) |
| Collection of Alex Earl | |
| Nickel et al. (1991) |
| Collected by and in the collection of ... |
| Bullock (1981) |
| Rocks & Minerals: 68 (6) |
| Bullock (1981) |
| Bullock (1981) | |
| Bullock (1981) |
| The Mineralogical Record: 22 (5) +3 other references | |
| Bullock (1981) |
| American Mineralogist: 46: 12-25. |
| Vochten et al. (1998) | |
| Honea (1961) |
| Honea (1961) |
Quick NavTopAbout BoltwooditeUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence Other LanguagesRelationshipsCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Goanikontes Claim, Goanikontes, Arandis Constituency, Erongo Region, Namibia