Dundasite

Summary

Dundasite is a rare lead aluminium carbonate mineral. The mineral is named after the type locality, Dundas, Tasmania, Australia.[2] The mineral was first discovered in the Adelaide Proprietary Mine.[5] Dundasite was first described by William Frederick Petterd in 1893.[6]

Dundasite
Dundasite (the white mineral) and crocoite from Dundas, Tasmania. Field of view is 5mm.
General
CategoryCarbonate mineral
Formula
(repeating unit)
PbAl2[(OH)2|CO3]2 • H2O
IMA symbolDun[1]
Strunz classification5.DB.10
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPbmm (no. 51)
Unit cella = 9.08, b = 16.37
c = 5.62 [Å]; Z = 4
Identification
ColorWhite to very pale blue; colorless in transmitted light
Crystal habitAcicular crystals typically in spherical aggregates and matted crusts
CleavagePerfect On {010}
Mohs scale hardness2
LusterVitreous to silky
StreakWhite
DiaphaneityTransparent
Specific gravity3.10 – 3.55
Optical propertiesBiaxial (-)
Refractive indexnα = 1.603 nβ = 1.716 nγ = 1.750
Birefringenceδ = 0.147
2V angleMeasured: 30° to 40°, calculated: 54°
References[2][3][4]

Dundasite is an uncommon secondary mineral occurring in the oxidized zone of lead ore deposits.[3] It commonly overgrows crocoite. It may also be overgrown by yellow cerussite.[5] It may be associated with cerussite, plattnerite, azurite, malachite, pyromorphite, mimetite, beudantite, duftite, crocoite, gibbsite, allophane and limonite.[3]

Besides its type location on Tasmania, the mineral has also been found in New Zealand, Mainland Australia, China, Belgium, Germany, France, Greece, United Kingdom, Ireland, Italy, Austria, Czech Republic, Namibia, and the US.[2]

References

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  Media related to Dundasite at Wikimedia Commons

  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. ^ a b c "Dundasite mineral information and data". mindat.org. Retrieved 31 December 2020.
  3. ^ a b c "Handbook of Mineralogy: Dunasite" (PDF). RRUF Database. Retrieved 31 December 2020.
  4. ^ "Dundasite Mineral Data". Webmineral. Retrieved 31 December 2020.
  5. ^ a b Bottrill, Ralph (April 12, 2009). "Dundasite". Retrieved 2009-10-16.
  6. ^ "Volume 14". The Mineralogical Magazine and Journal of the Mineralogical Society. Great Britain: Mineralogical Society. 1965.