Mindat Logo

Edgarite

Formula:
FeNb
 
3
S
 
6
System:HexagonalColour:Dark grey
Lustre:MetallicHardness:2 - 2½
Name:Named after Alan D. Edgar (1935–1998), Professor of Petrology, University of Western Ontario, London, Ontario, Canada, in recognition of his contributions to the study of alkaline rocks and synthetic equivalents.


A mineral that appears to have formed at a very late, or final, stage of metamorphism, after the main event of fenitization, from a highly reduced, subalkaline S-C-H-rich fluid, which may have remobilized Nb as a result of destabilization of oxide minerals (Barkov, et al (2000)).

Classification of Edgarite

IMA status:Approved 1995
Strunz 8th edition ID:2/D.07-20
Nickel-Strunz 10th (pending) edition ID:2.DB.25

2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
D : Metal Sulfides, M: S = 3 :4 and 2:3
B : M:S = 2:3
Dana 7th edition ID:2.11.13.1
mindat.org URL:http://www.mindat.org/min-6910.html
Please feel free to link to this page.

Type Occurrence of Edgarite

Type Locality:Kaskasnyunchorr, Khibiny Massif, Kola Peninsula, Murmanskaja Oblast', Northern Region, Russia
General Appearance of Type Material:Platy inclusions in Ti-(V)-rich pyrrhotite and ferroan alabandite, and as dark gray aggregates of platy grains.
Year of Discovery:2000
Geological Setting of type material:In a feldspar-rich fenitized xenolith approximately 200m across in foyaite at the Khibina alkaline complex.
Associated Minerals at type locality:
RutilePyrrhotitePhlogopiteMonazite-(Ce)Marcasite
MarcasiteCorundumAlabanditeWurtzite

Physical Properties of Edgarite

Lustre:Metallic
Diaphaneity (Transparency):Opaque
Colour:Dark grey
Hardness (Mohs):2 - 2½
Hardness (Vickers):VHN100=135 (5 s test time)
Density (calculated):4.99 g/cm3

Crystallography of Edgarite

Crystal System:Hexagonal
Class (H-M):6 2 2 - Trapezohedral
Space Group:P63 2 2
Cell Parameters:a = 5.771Å, c = 12.19Å
Ratio:a:c = 1 : 2.112
Unit Cell Volume:V 351.59 ų (Calculated from Unit Cell)
Z:2
Comment:Space group is probable
X-Ray Powder Diffraction:
d-spacingIntensity
6.11(80)
2.606(80)
2.096(100)

Optical Data of Edgarite

Type:Anisotropic
Anisotropism:White to dark brown
Reflectivity:
8.1nmR=8.%
27.4nmR=0.2(470%
27.0nmR=9.3(546%
27.0nmR=8.5(589%
nmR=6.9(650%


Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 9.3(546%.
Pleochroism:Strong
Comments:Grey to light grey with a bluish tint
Comments:Anisotropy strong.

Chemical Properties of Edgarite

Formula:
FeNb
 
3
S
 
6
Essential elements:Fe, Nb, S
All elements listed in formula:Fe, Nb, S
Analyical Data:
Nb(57.82)
Fe(10.12)
V(0.36)
Mn(0.10)
Ti(0.04)
S(35.86)
Empirical Formula:
(Fe
 
0.96
V
 
0.04
Mn
 
0.01
)
 
&
#931;
 
1.01
Nb
 
3.03
S
 
5.95
Common Impurities:V,Mn

Relationship of Edgarite to other Species

Related Minerals - Nickel-Strunz Grouping):
2.DB.05Antimonselite
Sb
 
2
Se
 
3
2.DB.05Bismuthinite
Bi
 
2
S
 
3
2.DB.05Guanajuatite
Bi
 
2
(Se,S)
 
3
2.DB.05Metastibnite
Sb
 
2
S
 
3
2.DB.05Pääkkönenite
Sb
 
2
AsS
 
2
2.DB.05Stibnite
Sb
 
2
S
 
3
2.DB.10Ottemannite
beta Sn
 
2
S
 
3
2.DB.10Suredaite
PbSnS
 
3
2.DB.15Bowieite
(Rh,Ir,Pt)
 
2
S
 
3
2.DB.15Kashinite
(Ir,Rh)
 
2
S
 
3
2.DB.20Montbrayite
(Au,Sb)
 
2
Te
 
3
2.DB.30Tarkianite
(Cu,Fe)(Re,Mo)
 
4
S
 
8
2.DB.35Cameronite
AgCu
 
7
Te
 
10

Other Names for Edgarite

Synonyms:
IMA1995-017
German names:
Edgarit
Russian names:
Эдгарит
Spanish names:
Edgarita

Other Information

Fluorescence in UV light:nonfluorescent
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 Edgarite

Reference List:Barkov, A.Y., R.F. Martin, Y.P. Men'shikov, Y.E. Savchenko, Y. Thibault, and K.V.O. Laajoki (2000) Edgarite, FeNb3S6, first natural niobium-rich sulfide from the Khibina alkaline complex, Russian Far North: evidence of chalcophile behavior of Nb in a fenite. Contributions to Mineralogy and Petrology: 138: 229-236.

Journal of Physics and Chemistry of Solids: 31: 1057-1067.

Journal of Solid State Chemistry: 33: 361-369.

Internet Links for Edgarite

Search Engines:
  • Look for Edgarite on Google
  • Look for Edgarite images on Google
  • External Links:
  • Look for Edgarite on Webmineral
  • Look for Edgarite on Athena Mineralogy
  • Look for Edgarite on Wikipedia
  • Look for Edgarite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Search for Edgarite in the Natural History Museum (London) online catalogue
  • Edgarite details from Handbook of Mineralogy (PDF)
  • Mineral Dealers:
  • Top quality minerals from Kristalle of California
  • Lapis Mineral Magazin
  • Search for Edgarite at Thames Valley Minerals
  • Buy from David K Joyce minerals
  • Buy fine minerals and gemstones from Pala International
  • Rare and Unusual minerals at Mineralogical Research Company
  • Wilensky Fine Minerals
  • e-Rocks - Mineral Auctions and Sales
  • rare and unusual minerals mainly crystallized
  • The Arkenstone - Fine Minerals
  • Fabre Minerals - search for Edgarite specimens
  • Search for Edgarite on minvision.com
  • Jobs:
  • Mining & Geology Jobs
  • Page Sponsor

    Sponsorship:This page is currently not sponsored. Click here to find out how you can sponsor this page.

    Localities for Edgarite

    (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.
    Russia
     
    • Northern Region
      • Murmanskaja Oblast'
        • Kola Peninsula
          • Khibiny Massif
    Barkov, A.Y., R.F. Martin, Y.P. Men'shikov, Y.E. Savchenko, Y. Thibault, and K.V.O. Laajoki (2000) Edgarite, FeNb3S6, first natural niobium-rich sulfide from the Khibina alkaline complex, Russian Far North: evidence of chalcophile behavior of Nb in a fenite. Contributions to Mineralogy and Petrology: 138: 229-236; The Canadian Mineralogist (2000): 38: 1377-1385.
    Mineral and/or Locality
    Google
     
    www.mindat.org Web
    Copyright © Jolyon & Ida Ralph 1993-2008. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them.Further information contact the 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 hundreds of members and supporters. If you would like to add information to improve the quality of our database, then click here to register.