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.^[7]

Aeschynite-(Ce)
General
Category	Oxide minerals
Formula	(Ce,Ca,Fe,Th)(Ti,Nb)2(O,OH)6
IMA symbol	Aes-Ce[1]
Strunz classification	4.DF.05
Dana classification	08.03.06.01
Crystal system	Orthorhombic Dipyramidal class
Space group	H-M symbol: (2/m 2/m 2/m) Space group: Pmnb
Unit cell	a = 11.08, b = 7.56 c = 5.37 [Å]; Z = 4
Identification
Formula mass	305.70 g/mol
Color	Brown, light brown, brownish black, yellow, black
Crystal habit	Acicular, massive
Cleavage	None
Fracture	Brittle - conchoidal
Tenacity	Brittle
Mohs scale hardness	5 - 6
Luster	Adamantine, resinous to waxy, sub-metallic; dull when altered
Streak	Nearly black to brown
Diaphaneity	Transparent to translucent
Specific gravity	4.52
Density	5.19
Optical properties	Isotropic when metamict
Refractive index	2.26
Other characteristics	Radioactive
References	[2][3][4][5][6]

The "-(Ce)" means it has more cerium than the yttrium variety aeschynite-(Y). Its Mohs scale rating is 5–6.

See also

• List of minerals