Mineralogy Database

Boltwoodite Mineral Data

Search Webmineral :

General Boltwoodite Information

Help on Chemical  Formula: Chemical Formula: HK(UO2)(SiO4)•1.5(H2O)
Help on Composition: Composition: Molecular Weight = 429.24 gm
   Potassium   9.11 %  K    10.97 % K2O
   Uranium    55.45 %  U    62.91 % UO2
   Silicon     6.54 %  Si   14.00 % SiO2
   Hydrogen    0.94 %  H     8.39 % H2O
   Oxygen     27.96 %  O
             ______        ______ 
             100.00 %       96.27 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: HK(UO2)(SiO4)•1.5(H2O)
Help on Environment: Environment: In the outer silicate zone of alteration surrounding hydrated uranyl oxides incrusting primary uraninite; also filling fractures at some distance from primary uraninite.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1956
Help on Locality: Locality: In the USA, from the Delta mine, Emery Co., Utah; the New Method mine, near Amboy, San Bernardino Co., California. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: For Bertram Borden Boltwood (1870-1927), radiochemist of Yale University, New Haven, Connecticut, USA, who devised the U-Pb method of measuring geologic time.
Help on Name Pronunciation: Name Pronunciation: Boltwoodite + Pronunciation Say BOLTWOODITE
Help on Synonym: Synonym: ICSD 86631
  PDF 35-490

Boltwoodite Image

Click Here for Larger   Image in a New Browser Window Images:
Click Here for Larger   Image


Comments: Sprays of boltwoodite covering matrix.
Location: Rossing, Namibia. Scale: Size Not Given.
© John Veevaert

Click Here for Larger   Image in a New Browser Window Images:
Click Here for Larger   Image


Comments: Bright yellow, prismatic crystals of boltwoodite.
Location: Rössing mine, Swakopmund District, Namibia. Scale: Picture size 2.5 mm.
© Paul M. Schumacher

Click Here for Larger   Image in a New Browser Window Images:
Click Here for Larger   Image


Comments: Yellow, globular aggregates of boltwoodite on a ferruginous matrix.
Location: Repete Mine, San Juan County, Utah, USA. Scale: See Image.
© Jeff Weissman / Photographic Guide to Mineral Species

Boltwoodite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =1.9201:1:1.7296
Help on Cell Dimensions: Cell Dimensions: a = 13.71, b = 7.14, c = 12.35, Z = 6; beta = 102.2° V = 1,181.63 Den(Calc)= 3.62
Help on Crystal System: Crystal System: Monoclinic - Sphenoidal H-M Symbol (2) Space Group: P 21
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 6.81(1), 3.4(0.9), 2.95(0.8),

Physical Properties of Boltwoodite

Help on Cleavage: Cleavage: {010} Perfect, {001} Distinct
Help on Color: Color: Yellow, Light yellow.
Help on Density: Density: 3.6
Help on Hardness: Hardness: 3.5-4 - Copper Penny-Fluorite
Help on Luminescence: Luminescence: Fluorescent, Short UV=dull green, Long UV=dull green.
Help on Luster: Luster: Vitreous - Pearly
Help on Streak: Streak: white

Optical Properties of Boltwoodite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.346 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.338 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1901,KPDmeas= 0.1912,KC= 0.1421
Ncalc = 1.51
Help on Optical Data: Optical Data: Biaxial (-), a=1.669, b=1.6955, g=1.7005, bire=0.0315
Help on Pleochroism (x): Pleochroism (x): colorless.
Help on Pleochroism (y): Pleochroism (y): colorless.
Help on Pleochroism (z): Pleochroism (z): colorless.

Calculated Properties of Boltwoodite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.19 gm/cc
note: Specific Gravity of Boltwoodite =3.62 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0071947992
Boson Index = 0.9928052008
Help on Photoelectric: Photoelectric: PEBoltwoodite =1,429.97 barns/electron
U=PEBoltwoodite x relectron=4,558.55 barns/cc.
Help on Radioactivity: Radioactivity:

GRapi = 4,162,622.33 (Gamma Ray American Petroleum Institute Units)
Concentration of Boltwoodite per GRapi unit = 240.23 (PPB)

Boltwoodite 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) 7.31 ± 1.83 grams of pure Boltwoodite .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 730.71 ±182.68 grams of pure Boltwoodite .

Estimated Radioactivity from Boltwoodite - very strong
Curies (Ci)
If Held in Hand
For One Hour
1000 gm / 8.08 cm 99,264,658 2.68E-03 4,162,622.33 1,368.53
100 gm / 3.75 cm 9,926,466 2.68E-04 416,262.23 136.85
10 gm / 1.74 cm 992,647 2.68E-05 41,626.22 13.69
1 gm / 8.08 mm 99,265 2.68E-06 4,162.62 1.37
0.1 gm / 3.75 mm 9,926 2.68E-07 416.26 0.14
0.01 gm / 1.74 mm 993 2.68E-08 41.63 0.01
0.001 gm / 0.81 mm 99 2.68E-09 4.16 0.00

Weight of pure Boltwoodite in grams (gm) and Calculated Diameter of a Sphere with a Density of 3.62 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

Boltwoodite Classification

Help on  Dana Class: Dana Class: (53)Nesosilicate Insular SiO4 Groups and Other Anions of Complex Cations
  (53.03)with (UO2)
  (53.03.01)Uranophane group Kasolite Pb(UO2)SiO4•(H2O) P 21/a 2/m Uranophane Ca(UO2)2SiO3(OH)2•5(H2O) P 21 2 Sklodowskite (H3O)2Mg(UO2)2(SiO4)2•4(H2O) C 2/m 2/m Cuprosklodowskite Cu[(UO2)(SiO2OH)]2•6(H2O) P1 1 Boltwoodite HK(UO2)(SiO4)•1.5(H2O) P 21 2 Natroboltwoodite (H3O)(Na,K)(UO2)SiO4•(H2O) P 212121 2 2 2 Oursinite (Co,Mg)(H3O)2[(UO2)SiO4]2•3(H2O) Aba2,Abam Ortho Swamboite UH6(UO2)6(SiO4)6•30(H2O) P 21/a 2/m Uranophane-beta Ca[(UO2)SiO3(OH)]2•(H2O) P 21/a 2/m
Help on  Strunz Class: Strunz Class: 09.AK.15 09 - SILICATES (Germanates)
  09.A - Nesosilicates
  09.AK -Uranyl neso- and polysilicates
09.AK.15 Boltwoodite HK(UO2)(SiO4)•1.5(H2O) P 21 2
09.AK.15 Kasolite Pb(UO2)SiO4•(H2O) P 21/a 2/m
09.AK.15 Uranophane Ca(UO2)2SiO3(OH)2•5(H2O) P 21 2
09.AK.15 Natroboltwoodite (H3O)(Na,K)(UO2)SiO4•(H2O) P 212121 2 2 2

Other Boltwoodite Information

Help on References: References: NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)
Help on See Also: See Also: Links to other databases for Boltwoodite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - EUROmin Project
5 - Ecole des Mines de Paris
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - Philatelic Mineralogy
15 - QUT Mineral Atlas
16 - Ruff.Info
17 - Scandinavian mineral gallery
18 - Uranium Minerals

Search for Boltwoodite using:

Web webmineral.com
[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Boltwoodite :

Ask about Boltwoodite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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


Dana No: Strunz No: 09.AK.15





Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.