Rhombohedral, but isotropic; apparently a pseudomorph after [Melanocerite] (q.v.)
G = 4·295. H = 5-6. Nut brown; translucent. Faces very brilliant, but striated. Lustre vitreous to resinous.
Various rocks and shoals round Arö Island, Langesund Fiord, Norway.
Castelnaudite.
A variety of [Xenotime] (q.v.) containing Zr. Yttr = 60·4; ZrO₂ = 7·4%.
Tetragonal.
G = 4·5. H = 4-5. Greyish white to pale yellow.
Diamond sands of Brazil.
Cataplejite (Kataplejite).
H₄(Na₂,Ca)ZrSi₃O₁₁. ZrO₂ = 29·6-40% (usually 30-33%).