Zircophyllite
A complex zirconium-niobium phyllosilicate forming dark mica-like plates.
Intro adapted from Wikipedia (CC BY-SA).
Zircophyllite is an IMA-recognized mineral species in the silicate class, with the chemical formula K₂NaFe²⁺₇Zr₂(Si₄O₁₂)₂O₂(OH)₄F.
It is a member of the Astrophyllite-Astrophyllite structural group.
Key properties: Mohs hardness 4–4.5; specific gravity 3.34; Pale brown streak; Vitreous to adamantine luster; optically biaxial.
IMA symbol Zcp, IMA status: approved, named in 1971.
Found in the natrolite zone of alkalic pegmatites.
It is found associated with \Aegirine-augite, " leucophanite, fluorite, apatite, apophyllite.
The name refers to ZIRCOnium in the composition and the Greek for leaf, in reference to its foliated, micaceous habit.