Dundasite (white) and Crocoite (red orange) from Dundas , Tasmania . — Photo: JJ Harrison ( https://www.jjharrison.com.au/ ) · CC BY-SA 3.0
Dundasite
A rare lead-aluminium carbonate named for its type locality at Dundas, Tasmania.
Intro adapted from Wikipedia (CC BY-SA).
Dundasite is an IMA-recognized mineral species in the carbonate class, with the chemical formula PbAl₂(CO₃)₂(OH)₄·H₂O.
It crystallizes in the orthorhombic crystal system (space group Pbnm). It is a member of the Dundasite structural group.
Key properties: Mohs hardness 2; specific gravity 3.1–3.55; Vitreous to silky luster; refractive index 1.69; optically biaxial.
IMA symbol Dun, grandfathered status — known before the IMA’s founding, named in 1894.
Uncommon in the oxidized zone of lead-bearing deposits.
It is found associated with Cerussite, plattnerite, azurite, malachite, pyromorphite, mimetite, beudantite, duftite, crocoite, gibbsite, allophane, “limonite”.
The name refers to the occurrence at Dundas, Tasmania, Australia.