Adamite (Var.: Manganoan Adamite), Lotharmeyerite Locality: Ojuela Mine, Mapimí , Municipio de Mapimí , Durango , Mexico ( Locality at mindat.org ) These rare crystals were found by John Whitmire. Crystals to 1.5 cm. Formerly in the collection and with label of Willard Perkins, the collector who invented the so-called "Perky Box" for thumbnails. (it also has microcrystals of lotharmeyerite: tiny dark red needles scattered on the black matrix. 2.7 x 2.5 x 1.8 cm — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Lotharmeyerite
Lotharmeyerite is an IMA-recognized mineral species in the arsenate class, with the chemical formula CaZn₂(AsO₄)₂·2H₂O.
It crystallizes in the monoclinic crystal system (space group C2/m). It is a member of the Natrochalcite structural group.
Key properties: Mohs hardness 3; specific gravity 4.23; Pale orange to yellow- orange streak; Vitreous luster; optically biaxial.
IMA symbol Lmy, IMA status: approved, named in 1982.
Found in the oxidized zone of an arsenic-rich polymetallic base-metal deposit.
It is found associated with Adamite, cryptomelane, chalcophanite, goethite.
The mineral was named to honor Julius Lothar Meyer (1830-1895), German chemist and physician, Karlsruhe Polytechnic Institute and University of Tübingen, Germany, for his contributions to chemistry.