Sharp orange octahedral crystals of the new mineral oxicalciopyrochlore from one of the very few known localities worldwide. From: Schelingen, Kaiserstuhl, Baden-Württemberg, Germany. — Photo: David Hospital · CC BY-SA 4.0
Oxycalciopyrochlore
Pyrochlore (Na,Ca)2Nb2O6(OH,F) is a mineral group of the niobium end member of the pyrochlore supergroup. Pyrochlore is also a term for the crystal structure Fd3m. The name is from the Greek πῦρ, fire, and χλωρός, green because it typically turns green on ignition in classic blowpipe analysis.
Intro adapted from Wikipedia (CC BY-SA).
Oxycalciopyrochlore is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Ca₂Nb₂O₆O.
It crystallizes in the cubic crystal system (space group Fd3m). It is a member of the Pyrochlore-Pyrochlore structural group.
Key properties: Mohs hardness 5; specific gravity 5.3; Pale brown to cream streak; Vitreous luster.
IMA symbol Ocpcl, IMA status: approved, named in 1977.
Occurs as replacement masses and in veinlets, in a granite pegmatite in a serpentinite.
It is found associated with Columbite, niobian rutile, antimony, stokesite, cassiterite, zircon, albite.
The name refers to a member of the pyrochlore group with prefixes to indicate dominant oxygen (oxy) in the Y site and dominant calcium (calcio) in the A site. Formerly ‘stibiobetafite’.