Mindat Logo

Downeyite

This page is currently not sponsored. Click here to sponsor this page.



Formula:
SeO
 
2
System:TetragonalColour:Colourless (red - ...
Lustre:Adamantine
Name:For Wayne F. Downey, Jr., who discovered the mineral. He was a high school student at the time.


Naturally occuring selenium(IV) oxide, extremely hygroscopic.

Classification of Downeyite

IMA status:Approved 1974
Strunz 8th edition ID:4/D.14-20
Nickel-Strunz 10th (pending) edition ID:4.DE.05

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
E : With medium-sized cations; with various polyhedra
Dana 8th edition ID:4.4.3.1

4 : SIMPLE OXIDES
4 : AX2
Hey's CIM Ref.:7.17.1

7 : Oxides and Hydroxides
17 : Oxides of Se and Te
mindat.org URL:http://www.mindat.org/min-1315.html
Please feel free to link to this page.

Type Occurrence of Downeyite

Type Locality:Forestville, Schuylkill Co., Pennsylvania, USA
General Appearance of Type Material:Acicular to prismatic crystals
Place of Conservation of Type Material:Smithsonian
Year of Discovery:1971
Geological Setting of type material:Burning anthracite culm banks

Occurrences of Downeyite

Geological Setting:Burning coal banks.

Physical Properties of Downeyite

Lustre:Adamantine
Diaphaneity (Transparency):Transparent
Colour:Colourless (red - included selenium, yelllow - included sulfur)
Density (calculated):4.146 g/cm3

Crystallography of Downeyite

Crystal System:Tetragonal
Cell Parameters:a = 8.36Å, c = 5.06Å
Ratio:a:c = 1 : 0.605
Unit Cell Volume:V 353.64 ų (Calculated from Unit Cell)
Morphology:Acicular crystals to 2 cm.

Optical Data of Downeyite

Type:Uniaxial (+)
Comments:Extremely hygroscopic. In air will deliquesce in a few minutes and be absorbed into substrate or evaporate leaving colorless film.

Chemical Properties of Downeyite

Formula:
SeO
 
2
Simplified for copy/paste:SeO2
Essential elements:O, Se
All elements listed in formula:O, Se

Relationship of Downeyite to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
4.DE.10Koragoite
(Mn
2+
 
,Fe
3+
 
)
 
3
(Nb,Ta,Ti)
 
2
(Nb,Mn)
 
2
(W,Ta)
 
2
O
 
20
4.DE.15Koechlinite
Bi
 
2
MoO
 
6
4.DE.15Russellite
Bi
 
2
WO
 
6
4.DE.15Tungstibite
Sb
3+
2
WO
 
6
4.DE.20Tellurite
TeO
 
2
4.DE.25Paratellurite
TeO
 
2
4.DE.30Bismutotantalite
Bi(Ta,Nb)O
 
4
4.DE.30Bismutocolumbite
Bi(Nb,Ta)O
 
4
4.DE.30Cervantite
Sb
3+
 
Sb
5+
 
O
 
4
4.DE.30Stibiotantalite
Sb(Ta,Nb)O
 
4
4.DE.30Stibiocolumbite
Sb(Nb,Ta)O
 
4
4.DE.30Clinocervantite
Sb
3+
 
Sb
5+
 
O
 
4
4.DE.35Baddeleyite
ZrO
 
2
Related Minerals - Hey's Index Grouping:

- +
7.17.2Tellurite
TeO
 
2
7.17.3Paratellurite
TeO
 
2
7.17.4Chiluite
Bi
 
3
Te
6+
 
Mo
6+
 
O
 
10.5

Other Names for Downeyite

Synonyms:
IMA1974-063
Other Languages:
German:Downeyit
Russian:Доунейит
Spanish:Downeyita

Other Information

Fluorescence in UV light:None
Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Downeyite

Reference List:

- +
Finkelman, R. B. & Mrose, M. E. (1977): Downeyite, the first verified natural occurrence of selenium dioxide. American Mineralogist 62, 316-320.

Journal of the American Chemical Society: 59: 789-794.

Internet Links for Downeyite

Search Engines:
  • Look for Downeyite on Google
  • Look for Downeyite images on Google
  • External Links:
  • Look for Downeyite on Webmineral
  • Look for Downeyite on Athena Mineralogy
  • Look for Downeyite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Downeyite details from Handbook of Mineralogy (PDF)
  • Mineral Dealers:
  • Wilensky Fine Minerals
  • Rare and Unusual minerals at Mineralogical Research Company
  • DAKOTA MATRIX offers Cabinet and Rare Species from Worldwide Localities.
  • Fine and rare minerals from mintreasure.com
  • Fine minerals from bisbeeborn.com
  • Fabre Minerals - search for Downeyite specimens
  • Top quality minerals from Kristalle of California
  • Buy from McDougall Minerals
  • The Arkenstone - Fine Minerals
  • Buy minerals from YourMineralCollection
  • Search for Downeyite on Well-Arranged Molecules
  • rare and unusual minerals mainly crystallized
  • Jobs:
  • Mining & Geology Jobs
  • Localities for Downeyite

    The 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.
    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    USA
     
    • Pennsylvania
      • Northumberland Co.
    Mineralogy associated with burning Anthracite deposits of Eastern Pennsylvania, D. M. Lapham, J. H. Barns, W. Downey Jr. and R. B. Finkelman, Min. Rescs. Report #78, 1980
      • Schuylkill Co.
    Finkelman, R.B. & Mrose, M.E. (1977) American Mineralogist: 62,316-320.
    Mineral and/or Locality  
    Search Google  
    Copyright © Jolyon Ralph and Ida Chau 1993-2014. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of thousands of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
    Current server date and time: March 11, 2014 12:31:39
    Mineral and Locality Search
    Mineral:
    and/or Locality:
    Options
    Fade toolbar when not in focusFix toolbar to bottom of page
    Hide Social Media Links
    Slideshow frame delay seconds