Paradamite Locality: Mina Ojuela, Mapimi, Durango, Mexico Size: thumbnail, 1.8 x 1.1 x 0.5 cm Paradamite A thumbnail of this rare species of super quality, from famous finds at Ojuela in the 1970s! It is very hard to obtain this mineral today - it is much rarer even then legrandite, in my experience, on the market. This is a killer thumbnail example, too, in aesthetic form and complete all around! — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Paradamite
A very rare zinc arsenate — the triclinic dimorph of adamite, same formula but different atomic arrangement.
Intro adapted from Wikipedia (CC BY-SA).
Paradamite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Zn₂(AsO₄)(OH).
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Tarbuttite structural group.
Key properties: specific gravity 4.55; White streak; Vitreous, pearly on cleavages luster; optically biaxial.
IMA symbol Prd, grandfathered status — known before the IMA’s founding, named in 1956.
A rare secondary mineral found in the oxidized zone of some hydrothermal polymetallic base-metal deposits.
It is found associated with Mimetite, adamite, ojuelaite, mapimite, “limonite” (Ojuela mine, Mexico); köttigite, adamite, smithsonite, wulfenite, chalcocite (Tsumeb, Namibia).
Its name comes from the Greek para, for near, and its dimorphous relation to adamite.