A silico-columbate of E, Zr, Ca, Fe, Na, K; R₂Cb₂F₂SiO₉, where R represents various metals. E = 3·41; ZrO₂ = 5·7%.
Cubic, in small octahedra.
G = 3·77. H = 51⁄2. Greenish brown; opaque. Metallic lustre (χαλκός = Copper, λαμπρός = lustre).
Narsarsuk, S. Greenland.
Churchite.
Hydrous phosphate of Cerium metals and Ca; Cer = 51·87%.
Monoclinic? Allegations only.
G = 3·14. H = 31⁄2. Greyish; transparent to translucent.
Cornwall.