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Mary Duke Biddle
Bi3+24Cr6+8O57(OH)6 · 3H2O
Yellow to dirty yellow-brown
3 - 4
Specific Gravity:
7.171 (Calculated)
Crystal System:
Named for Duke University (North Carolina), as the holotype specimen was discovered in its colelctions, and for the Duke family. The discoverers of the mineral also note that the name acknowledges the Mary Duke Biddle Foundation 'for its support of mineralogical research that directly led to the initial discovery of the mineral.'
Unique combination of elements. Third natural bismuth-bearing chromate after chrombismite and 'unnamed (Bi chromate oxide)'.

The structure is based on irregular layers of Biφn polyhedra, with φ being O, OH, and H2O; the layers are parallel to (001), linked together by chromate tetrahedra. One of chromate groups shares all vertices with bismuth polyhedra, while the other three chromate groups have only three vertices shared.

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Classification of DukeiteHide

Approval Year:
First Published:

7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
F : With large and medium-sized cations
Dana 7th ed.:

Pronounciation of DukeiteHide

PlayRecorded byCountry
Jolyon & Katya RalphUnited Kingdom

Physical Properties of DukeiteHide

Yellow to dirty yellow-brown
Bright Yellow
3 - 4 on Mohs scale
7.171 g/cm3 (Calculated)

Optical Data of DukeiteHide

RI values:
nα = 2.330 nβ = 2.370
Max Birefringence:
δ = 2.330
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Very High
Very weak
Colour in reflected light:
Gray to purplish gray
Internal Reflections:
Yellow (strong)

Chemical Properties of DukeiteHide

Bi3+24Cr6+8O57(OH)6 · 3H2O
Common Impurities:

Crystallography of DukeiteHide

Crystal System:
Class (H-M):
3m - Ditrigonal Pyramidal
Space Group:
P3 1c
Cell Parameters:
a = 15.067(3) Å, c = 15.293(4) Å
a:c = 1 : 1.015
Unit Cell V:
3007 ų

Type Occurrence of DukeiteHide

General Appearance of Type Material:
grouped sheaves / acicular crystals, possibly pseudomorphous after unnamed phase; aggregates are 1 x 0.3 mm2, and individuals up to 100 x 1-2 µm
Place of Conservation of Type Material:
Smithsonian Institution, Washington (catalogue number 172012)
Associated Minerals at Type Locality:
Burns, P.C., Roberts, A.C., Stirling, J.A.R., Criddle, A.J., Feinglos, M.N. (2000) Dukeite, Bi243+Cr86+O57(OH)6(H2O)3, a new mineral from Brejauba, Minas Gerais, Brazil: description and crystal structure. American Mineralogist: 85: 1822-1827.

Synonyms of DukeiteHide

Other Language Names for DukeiteHide


Related Minerals - Nickel-Strunz GroupingHide

7.DF.Aldridgeite(Cd,Ca)(Cu,Zn)4(SO4)2(OH)6 · 3H2O Mon. 2/m : B2/b
7.DF.AlcaparrosaiteK3Ti4+Fe3+(SO4)4O(H2O)2Mon. 2/m : B2/b
7.DF.05UklonskoviteNaMg(SO4)F · 2H2OMon.
7.DF.10KainiteKMg(SO4)Cl · 3H2OMon. 2/m : B2/m
7.DF.15NatrochalciteNaCu2(SO4)2(OH) · 2H2OMon. 2/m : B2/m
7.DF.20MetasideronatriteNa2Fe(SO4)2(OH) · H2OOrth. mmm (2/m 2/m 2/m)
7.DF.20SideronatriteNa2Fe(SO4)2(OH) · 3H2OOrth. 2 2 2 : P21 21 21
7.DF.25DespujolsiteCa3Mn4+(SO4)2(OH)6 · 3H2OHex. 6 m2 : P62c
7.DF.25FleischeritePb3Ge(SO4)2(OH)6 · 3H2OHex. 6/mmm (6/m 2/m 2/m) : P63/mmc
7.DF.25SchaurteiteCa3Ge(SO4)2(OH)6 · 4H2OHex. 6/mmm (6/m 2/m 2/m) : P63/mmc
7.DF.25MallestigitePb3Sb5+(SO4)(AsO4)(OH)6 · 3H2OHex. 6 : P63
7.DF.30Slavíkite(H3O+)3Mg6Fe15(SO4)21(OH)18 · 98H2OTrig. 3 : R3
7.DF.35MetavoltineNa6K2FeFe6(SO4)12O2 · 18H2OTrig.
7.DF.40LannoniteMg2Ca4Al4(SO4)8F8 · 24H2O Tet. 4/m : I4/m
7.DF.40VlodavetsiteAlCa2(SO4)2F2Cl · 4H2OTet. 4/m : I4/m
7.DF.45PeretaiteCa(SbO)4(SO4)2(OH)2 · 2H2OMon. 2/m : B2/b
7.DF.50GordaiteNaZn4(SO4)(OH)6Cl · 6H2OTrig. 3 : P3
7.DF.55Clairite(NH4)2Fe3(SO4)4(OH)3 · 3H2OTric.
7.DF.60ArzruniteCu4Pb2(SO4)(OH)4Cl6 · 2H2O (?)Orth.
7.DF.65ElyitePb4Cu(SO4)O2(OH)4 · H2OMon. 2/m
7.DF.70YecoraiteFe3+3Bi5(Te6+O4)2(Te4+O3)O9 · 9H2O
7.DF.75RiomarinaiteBi(SO4)(OH) · H2OMon. 2/m
7.DF.85XocolatliteCa2Mn4+2(Te6+O6)2 · H2OMon. 2/m : P2/m

Fluorescence of DukeiteHide

Other InformationHide

Slowly soluble in HCl
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 DukeiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Burns, P.C., Roberts, A.C., Stirling, J.A.R., Criddle, A.J., Feinglos, M.N. (2000) Dukeite, Bi243+Cr86+O57(OH)6(H2O)3, a new mineral from Brejauba, Minas Gerais, Brazil: description and crystal structure. American Mineralogist: 85: 1822-1827.

Internet Links for DukeiteHide

Localities for DukeiteHide

This 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.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - 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.
Brazil (TL)
  • Minas Gerais
    • Conceição do Mato Dentro
      • São José de Brejaúba
[MinRec 32:416]
  • Grand Est
    • Vosges
Georges Favreau
  • Honshu Island
    • Chubu Region
      • Nagano Prefecture
        • Chino City
Akira Harada, Takashi Yamada, Satoshi Matsubara, Ritsuro Miyawaki, Masako Shigeoka, Hiroshi Miyajima, Hiroshi Sakurai (2010) Bi-bearing secondary minerals from the Kinkei mine, Chino City, Nagano Prefecture, Japan. (conf. abstr. available at: ); Akira Harada, Takashi Yamada, Satoshi Matsubara, Ritsuro Miyawaki, Masako Shigeoka, Hiroshi Miyajima and Hiroshi Sakurai (2012) Dukeite from the Kinkei mine, Chino City, Nagano Prefecture, Japan. Bull. Natl. Mus. Nat. Sci., Ser. C, 38, 1–5, December 22, 2012.
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