Aeschynite-(Ce)
Aeschynite-(Ce) (or Aschynite, Eschinite, Eschynite) is a rare earth mineral of cerium, calcium, iron, thorium, titanium, niobium, oxygen, and hydrogen with chemical formula (Ce,Ca,Fe,Th)(Ti,Nb)2(O,OH)6. Its name comes from the Greek word αισχύνη ("aeschyne") for "shame" because early chemists had difficulty with separations of titanium from zirconium. The "-(Ce)" means it has more cerium than the yttrium variety aeschynite-(Y). Its Mohs scale rating is 5–6.
Intro adapted from Wikipedia (CC BY-SA).
Aeschynite-(Ce) is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (Ce,Ca,Fe,Th)(Ti,Nb)₂(O,OH)₆.
It crystallizes in the orthorhombic crystal system. It is a member of the Aeschynite structural group.
Key properties: Mohs hardness 5–6; specific gravity 5.19; Nearly black to brown streak; Submetallic, resinous to waxy; dull when altered luster; optically isotropic.
IMA symbol Aes-Ce, IMA status: approved, named in 1830.
Found in nepheline syenites and alkali syenite massifs; in granite pegmatites; in carbonatites in alkalic rocks; a detrital mineral in placers.
It is found associated with Feldspar, zircon, samarskite, columbite, allanite, titanite.
Its name comes from the Greek for shame, in allusion to the fact that early chemists had difficulty with separations of titanium from zirconium in some samples.