Zirkelite Field of view: 2 mm Locality: Jacupiranga Alkaline Complex, Cajati, São Paulo, Brazil — Photo: Izaac da Silva Leite · Public domain
Zirkelite
A black cubic zirconium-titanium oxide of the pyrochlore group — hardness 5.5.
Intro adapted from Wikipedia (CC BY-SA).
Zirkelite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (Ti,Ca,Zr)O₂₋ₓ.
It crystallizes in the hexagonal crystal system (space group C2/c). It is a member of the Fluorite structural group.
Key properties: Mohs hardness 5.5; specific gravity 4.741; Resinous luster.
IMA symbol Zke, IMA status: approved, named in 1895.
Found in a magnetite-pyroxenite carbonatite (Jacupiranga, Brazil); a late-stage differentiate in a layered intrusion (Rhum, Scotland).
It is found associated with Perovskite, baddeleyite.
The mineral was named to honor Ferdinand Zirkel (1838–1912), German petrographer, Professor of Mineralogy, University of Leipzig, Leipzig, Germany.