Gilmarite , Conichalcite Locality: El Guanaco Mine, Guanaco (Huanaco) , Santa Catalina , Antofagasta Province , Antofagasta Region , Chile ( Locality at mindat.org ) Greenish blue Gilmarite together with some Conichalcite spheres and light blue acicular xls of an unknown mineral. Field of view 7 mm. Specimen and photo Leon Hupperichs. — Photo: Leon Hupperichs · CC BY-SA 3.0
Gilmarite
Gilmarite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Cu²⁺₃(AsO₄)(OH)₃.
It crystallizes in the triclinic crystal system (space group P1). It is a member of the Gilmarite structural group.
Key properties: Mohs hardness 3; specific gravity 4.2; Blue-green streak; Vitreous luster; optically biaxial.
IMA symbol Gmr, IMA status: approved, named in 1996.
A rare secondary mineral in association with other copper arsenates and copper arsenides in the oxidized zone.
It is found associated with Cuprite, posnjakite, langite, clinotyrolite, connellite, brochantite, malachite, vésigniéite, cornubite, olivenite, trippkeite, domeykite, djurleite.
The mineral was named to honor Gilbert Mari (1944–), mineralogist, University of Nice-Sophia Antipolis, Nice, France, who collected the samples in which the mineral was found.