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Sidwillite

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About SidwilliteHide

Sidney A. Williams
Formula:
MoO3 · 2H2O
Colour:
Canary-yellow
Lustre:
Resinous
Hardness:
Specific Gravity:
3.12
Crystal System:
Monoclinic
Name:
Named in 1985 by Fabian Cesbron and Daria Ginderow in honor of Sidney Arthur Williams [December 26, 1933 Ann Arbor, Michigan, USA - December 8, 2006 Douglas, Arizona, USA], mineralogist, Phelps Dodge Corporation, Douglas, Arizona, USA. Sid Williams had a profound interest in systematic mineralogy and systematic language. His choice of using native languages of the region from where he named a mineral is unmatched in mineralogy.
This page provides mineralogical data about Sidwillite.


Classification of SidwilliteHide

Approved
Approval Year:
1983
First Published:
1985
4.FJ.05

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
J : Hydroxides with H2O +- (OH); corner-sharing octahedra
4.5.6.1

4 : SIMPLE OXIDES
5 : AX3
7.15.3

7 : Oxides and Hydroxides
15 : Oxides of Mo and W

Physical Properties of SidwilliteHide

Resinous
Comment:
(Cesbron and Ginderow 1985)
Colour:
Canary-yellow
Comment:
pleochroic, colorless - yellow at 47° ^ a-axis (Cesbron and Ginderow 1985)
Hardness:
2½ on Mohs scale
Cleavage:
Perfect
[010] (Cesbron and Ginderow 1985)
Density:
3.12 g/cm3 (Measured)    3.11 g/cm3 (Calculated)
Comment:
Data from Cesbron and Ginderow 1985

Optical Data of SidwilliteHide

Type:
Biaxial (-)
RI values:
nα = 1.700 nβ = 2.210 nγ = 2.380
2V:
Measured: 48° , Calculated: 48°
Max Birefringence:
δ = 0.680
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Very High
Dispersion:
relatively weak

Chemical Properties of SidwilliteHide

Formula:
MoO3 · 2H2O

Crystallography of SidwilliteHide

Crystal System:
Monoclinic
Cell Parameters:
a = 10.61 Å, b = 13.82 Å, c = 10.48 Å
β = 91.61°
Ratio:
a:b:c = 0.768 : 1 : 0.758
Unit Cell V:
1,536.08 ų (Calculated from Unit Cell)

Type Occurrence of SidwilliteHide

Place of Conservation of Type Material:
Collection de Mineralogie de I'Ecole nationale superieure
des Mines de Paris.
Geological Setting of Type Material:
quartz vein
Associated Minerals at Type Locality:
Reference:
Cesbron, F., Ginderow, D. (1985) Sidwillite MoO3·2H2O; a new mineral species from Lake Como, Colorado, U.S.A. Bulletin de la Société française de Minéralogie et de Cristallographie 108: 813-823.

Synonyms of SidwilliteHide

Other Language Names for SidwilliteHide

German:Sidwillit
Simplified Chinese:黄钼矿
Spanish:Sidwillita

Related Minerals - Nickel-Strunz GroupingHide

4.FJ.05MeymaciteWO3 · 2H2OAmor.
4.FJ.10TungstiteWO3 · H2OOrth.
4.FJ.15HydrotungstiteWO3 · 2H2OMon.
4.FJ.15IlsemanniteMo3O8 · nH2O

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

7.15.1TugarinoviteMoO2Mon.
7.15.2MolybditeMoO3Orth.
7.15.4IlsemanniteMo3O8 · nH2O
7.15.5TungstiteWO3 · H2OOrth.
7.15.6HydrotungstiteWO3 · 2H2OMon.
7.15.7MeymaciteWO3 · 2H2OAmor.
7.15.8Alumotungstite2W2O6(H2O)Iso. m3m (4/m 3 2/m) : Fd3m
7.15.9JixianitePb(W,Fe3+)2(O,OH)7Iso. m3m (4/m 3 2/m) : Fd3m

Other InformationHide

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

References for SidwilliteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Lindqvist, I. (1950) The crystal structure of the yellow molybdic acid, MoO3·2H2O. Acta Chemica Scandinavica: 4: 650-657.
Krebs, B. (1972) Die kristallstruktur von MoO3·2H2O. Acta Crystallographica: B28: 2222-2231.
Cesbron, F., Ginderow, D. (1985) Sidwillite MoO3·2H2O; a new
mineral species from Lake Como, Colorado, U.S.A. Bulletin de la Société française de Minéralogie et de Cristallographie 108: 813-823.
Grice J.D. (1986) New mineral names - sidwillite. American Mineralogist: 71: 1546.

Internet Links for SidwilliteHide

Localities for SidwilliteHide

ⓘ - Click for 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 (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
USA (TL)
 
  • Colorado
    • San Juan Co.
"Minerals of Colorado, updated & revised", p. 437, by Eckel, Edwin B., 1997
  • New Mexico
    • Luna Co.
      • Cookes Peak District
Ramon S. DeMark; Dr. Virgil W Lueth; Abstract, "A New Mexico Occurrence of sidwillite and other molybdenum minerals", 37th Annual New Mexico Mineral Symposium
  • Utah
    • Piute Co.
      • Marysvale District (Marysvale Uranium area)
Collected by and in the collection of Brent Thorne. SEM EDS and XRD analyzed by Andy Roberts.
Mineral and/or Locality  
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