Yellow brown crystals of the rare mineral nickellotharmeyerite grown inside negative quartz crystals. A mineral oddity from the type locality (Pucher Shaft, Erzgebirge, Saxony, Germany). The mineral has only been found in three localities worldwide! — Photo: David Hospital · CC BY-SA 4.0
Nickellotharmeyerite
Nickellotharmeyerite is an IMA-recognized mineral species in the arsenate class, with the chemical formula CaNi₂(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 4.5; specific gravity 4.45; Light brown to yellow streak; Subadamantine luster; optically biaxial.
IMA symbol Nlmy, IMA status: approved, named in 1999.
Found in the oxidation zone of polymetallic ore deposits.
It is found associated with Quartz, mawbyite, cobaltlotharmeyerite, galena, arseniosiderite, plumbogummite (Pucher shaft); nickeltsumcorite, annabergite, nickellotharmeyerite.
The prefix, nickel, indicates the nickel analog of lotharmeyerite.