Walfordite
Walfordite from Tambo Mine, Elqui Province, Chile
General
CategoryTellurite minerals
Formula
(repeating unit)
Fe3+,Te6+Te4+3O8
IMA symbolwfd[1]
Strunz classification4.JK.05
Crystal systemIsometric
Space groupI2, Ia3
Unit cella = 11.011 Å ; Z = 8
Identification
ColourOrange
Crystal habitMicroscopic cubic crystals
CleavageNone
TenacityBrittle
LusterAdamantine
StreakOrange-yellow
DiaphaneityOpaque
Specific gravity5.841 (calculated)
Optical propertiesIsotropic
Refractive indexn = 2.23
References[2][3][4]

Walfordite is a very rare tellurite mineral that was discovered in Chile in 1999.[5] The mineral is described as orange with orange-yellow streak, and is determined to have a chemical formula of Fe3+,Te6+Te4+3O8[2] with minor titanium and magnesium substitution resulting in an approximate empirical formula of (Fe3+,Te6+,Ti4+,Mg)(Te4+)3O8.[5]

Occurrence

The only reported occurrence[3] is in the Wendy open pit, El Indio-Tambo mining district of the Coquimbo Region, northern Chile where it occurs in oxidized breccia associated with a tellurium-bearing gold deposit. Associated minerals include: alunite, rodalquilarite, native gold, emmonsite, jarosite and pyrite. The mineral was named for mine geologist Phillip Walford (1945— ) who first noted the mineral.[2]

See also

References

  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. 1 2 3 Walfordite in the Handbook of Mineralogy
  3. 1 2 Walfordite on Mindat.org
  4. Walfordite data on Webmineral
  5. 1 2 Back, Malcolm E.; Grice, Joel D.; Gault, Robert A.; Criddle, Alan J.; Mandarino, Joseph A. (1999). "Walfordite, a New Tellurite Species from the Wendy Open Pit, El Indio - Tambo Mining Property, Chile" (PDF). The Canadian Mineralogist. 37: 1261–1268.
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