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Eskolaite

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Outokumpu, Itä-Suomen Lääni, Finland
© 2004 M. Kampf

Formula:
Cr
 
2
O
 
3
System:TrigonalColour:Black
Hardness:8 - 8½
Name:After Professor Pentti Eelis Eskola (1883–1964), University of Helsinki, Helsinki, Finland.


Hematite Group.
The chromium analogue of Corundum, Hematite, and Karelianite.

Classification of Eskolaite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:4/C.04-30
Nickel-Strunz 10th (pending) edition ID:4.CB.05

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
C : Metal: Oxygen = 2: 3,3: 5, and similar
B : With medium-sized cations
Dana 8th edition ID:4.3.1.3

4 : SIMPLE OXIDES
3 : A2X3
Hey's CIM Ref.:7.14.1

7 : Oxides and Hydroxides
14 : Oxides of Cr
mindat.org URL:http://www.mindat.org/min-1411.html
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Type Occurrence of Eskolaite

Type Locality:Outokumpu, Itä-Suomen Lääni, Finland
Year of Discovery:1958

Physical Properties of Eskolaite

Lustre:Metallic
Colour:Black
Streak:Green
Hardness (Mohs):8 - 8½

Crystallography of Eskolaite

Crystal System:Trigonal
Cell Parameters:a = 4.95Å, c = 13.58Å
Ratio:a:c = 1 : 2.743
Unit Cell Volume:V 288.16 ų (Calculated from Unit Cell)

Chemical Properties of Eskolaite

Formula:
Cr
 
2
O
 
3
Essential elements:Cr, O
All elements listed in formula:Cr, O
Common Impurities:V

Relationship of Eskolaite to other Species

Related to:
  • Hematite Group
    • Related Minerals - Nickel-Strunz Grouping):
    4.CB.05Brizziite
    NaSb
    5+
     
    		O
     
    3
    4.CB.05Corundum
    Al
     
    2
    		O
     
    3
    4.CB.05Ecandrewsite
    (Zn,Fe
    2+
     
    		,Mn
    2+
     
    		)TiO
     
    3
    4.CB.05Geikielite
    MgTiO
     
    3
    4.CB.05Hematite
    Fe
     
    2
    		O
     
    3
    4.CB.05Ilmenite
    Fe
    2+
     
    		TiO
     
    3
    4.CB.05Karelianite
    V
     
    2
    		O
     
    3
    4.CB.05Melanostibite
    Mn
    2+
     
    		(Sb
    5+
     
    		,Fe
    3+
     
    		)O
     
    3
    4.CB.05Pyrophanite
    Mn
    2+
     
    		TiO
     
    3
    4.CB.05Auroantimonate
    AuSbO
     
    3
    4.CB.05Romanite
    ([],Pb,Ca)UFe
    2+
    2
    		(Ti,Fe
    3+
     
    		)
     
    6
    		Ti
     
    12
    		O
     
    38
    4.CB.10Avicennite
    Tl
     
    2
    		O
     
    3
    4.CB.10Bixbyite
    (Mn
    3+
     
    		,Fe
    3+
     
    		)
     
    2
    		O
     
    3
    4.CB.15Armalcolite
    (Mg,Fe
    2+
     
    		)Ti
     
    2
    		O
     
    5
    4.CB.15Pseudobrookite
    Fe
     
    2
    		TiO
     
    5
    4.CB.15Mongshanite
    (Mg,Cr,Fe
    2+
     
    		)
     
    2
    		(Ti,Zr)
     
    5
    		O
     
    12
    4.CB.20Zincohögbomite-2N2S
    Ti(Zn,Mg,Fe)
     
    2
    		Al
     
    8
    		O
     
    15
    		(OH)
    4.CB.20Zincohögbomite-2N6S
    Ti(Zn,Mg,Fe)
     
    6
    		Al
     
    16
    		O
     
    31
    		(OH)
    4.CB.20Magnesiohögbomite-6N6S
    Ti(Mg,Fe)
     
    2
    		Al
     
    8
    		O
     
    15
    		(OH)
    4.CB.20Magnesiohögbomite-2N3S
    Ti(Mg,Fe)
     
    3
    		Al
     
    10
    		O
     
    19
    		(OH)
    4.CB.20Magnesiohögbomite-2N2S
    Ti(Mg,Fe)
     
    2
    		Al
     
    8
    		O
     
    15
    		(OH)
    4.CB.20Ferrohögbomite-6N12S
    Ti(Fe,Mg)
     
    4
    		Al
     
    12
    		O
     
    23
    		(OH)
    4.CB.25Pseudorutile
    Fe
     
    2
    		Ti
     
    3
    		O
     
    9
    4.CB.25Tietaiyangite
    Fe
    3+
    4
    		Fe
    2+
     
    		TiO
     
    9
    4.CB.30Berdesinskiite
    V
    3+
    2
    		TiO
     
    5
    4.CB.35Kyzylkumite
    V
     
    2
    		Ti
     
    3
    		O
     
    9
    4.CB.35Olkhonskite
    (Cr,V)
     
    2
    		Ti
     
    3
    		O
     
    9
    4.CB.35Schreyerite
    V
     
    2
    		Ti
     
    3
    		O
     
    9
    4.CB.40Kamiokite
    Fe
     
    2
    		Mo
     
    3
    		O
     
    8
    4.CB.40Nolanite
    (V,Fe,Fe,Ti)
     
    10
    		O
     
    14
    		(OH)
     
    2
    4.CB.40Rinmanite
    Zn
     
    2
    		Sb
     
    2
    		Mg
     
    2
    		Fe
     
    4
    		O
     
    14
    		(OH)
     
    2
    4.CB.45Claudetite
    As
     
    2
    		O
     
    3
    4.CB.45Stibioclaudetite
    AsSbO
     
    3
    4.CB.50Arsenolite
    As
     
    2
    		O
     
    3
    4.CB.50Sénarmontite
    Sb
     
    2
    		O
     
    3
    4.CB.55Valentinite
    Sb
     
    2
    		O
     
    3
    4.CB.60Bismite
    Bi
     
    2
    		O
     
    3
    4.CB.65Sphaerobismoite
    Bi
     
    2
    		O
     
    3
    4.CB.70Sillénite
    Bi
     
    12
    		SiO
     
    20
    Related Minerals - Hey's Index Grouping:
    7.14.2Bracewellite
    CrO(OH)
    7.14.3Grimaldiite
    CrO(OH)
    7.14.4Guyanaite
    CrO(OH)
    7.14.5Yimengite
    K(Cr,Ti,Fe,Mg)
     
    12
    		O
     
    19
    7.14.6Mathiasite
    K(Ti,Cr,Fe,Mg,Zr)
     
    21
    		O
     
    38
    7.14.7Mcconnellite
    CuCrO
     
    2
    7.14.8Redledgeite
    Ba
     
    x
    		([Cr,Fe,V]
    3+
    2x
    		Ti
     
    8-2x
    		)O
     
    16
    7.14.9Hawthorneite
    BaMgTi
     
    3
    		Cr
     
    4
    		Fe
     
    4
    		O
     
    19
    7.14.10Zincochromite
    ZnCr
     
    2
    		O
     
    4
    7.14.11Wattersite
    (Hg-Hg)
    2+
    2
    		Hg
    2+
     
    		[O
     
    2
    		|CrO
     
    4
    		]
    7.14.12Chromite
    FeCr
     
    2
    		O
     
    4
    7.14.13Magnesiochromite
    MgCr
     
    2
    		O
     
    4
    7.14.14 Donathite

    Other Names for Eskolaite

    German names:
    Eskolait
    Russian names:
    Эсколаит
    Spanish names:
    Eskolaita

    Other Information

    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 Eskolaite

    Reference List:American Mineralogist: 43: 1098-1106.

    Zeitschrift für Kristallographie: 117: 233-237.

    Internet Links for Eskolaite

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  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Search for Eskolaite in the Natural History Museum (London) online catalogue
  • Eskolaite details from Handbook of Mineralogy (PDF)
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    Localities for Eskolaite

    Hide Locality List
    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.
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    (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.
    Brazil
     
    • Northeast Region
      • Bahia
        • Érico Cardoso (old Água Quente)
          • Paramirim das Crioulas
    		Anthony, J. W. et al. (1997): Handbook of Mineralogy, Vol. 3, 33
    Jeannine and Jacques Cassedanne : "Présence d'eskolaite dans les alluvions stannifères de la Chapada Diamantina (Bahia-Brésil), Bull. Mineral., 1980, 103, pp 600-602.
        • Paramirim
    		[MinRec 16:111]
    Finland
     
    • Itä-Suomen Lääni
    		Am Min 43 (1958), 1098
    Guyana
     
    • Mazaruni District
      • Kamakusa
    		No reference listed
    Oman
     
    • Dhofar (Al Janubiyah) Province
    Russia
     
    • Eastern-Siberian Region
      • Transbaikalia (Zabaykalye)
        • Buriatia (Buryatia) Republic
          • Baikal area
            • Sludyanka (Slyudyanka)
              • Pokhabikha River Valley
        • Irkutskaya Oblast'
          • Lake Baikal area
    		[MinRec 27:304]
    • Northern Region
      • Murmanskaja Oblast'
        • Kola Peninsula
    		www.koeln.netsurf.de/~w.steffens/khib.htm
    USA
     
    • California
      • San Benito Co.
        • New Idria District
    		Dunning, Hadley, Cooper, Magnasco collections
    Mineral and/or Locality
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