Cerite

Cerite is a complex silicate mineral group containing cerium, formula (Ce,La,Ca)
₉(Mg,Fe³⁺
)(SiO
₄)
₆(SiO
₃OH)(OH)
₃.^[3] The cerium and lanthanum content varies with the Ce rich species (cerite-(Ce)) and the La rich species (cerite-(La)).^[5][6] Analysis of a sample from the Mountain Pass carbonatite gave 35.05% Ce
₂O
₃ and 30.04% La
₂O
₃.^[3]

Cerite
Cerite – Bastnas – Deposit Topotype
General
Category	Silicate mineral group
Formula	(Ce,La,Ca) 9(Mg,Fe3+ )(SiO 4) 6(SiO 3OH)(OH) 3
IMA symbol	Crt[1]
Crystal system	Trigonal
Crystal class	Ditrigonal pyramidal (3m) (same H-M symbol)
Space group	R3c
Identification
Color	Clove-brown with a reddish tinge; pale lavender-brown to colorless in thin fragments
Crystal habit	Massive granular
Cleavage	None
Fracture	Uneven
Mohs scale hardness	5 to 5.5
Luster	Vitreous to resinous
Streak	White to greyish white
Diaphaneity	Subtranslucent to opaque
Specific gravity	4.7 to 4.86
Optical properties	Uniaxial (+)
Refractive index	nω = 1.806 – 1.810 nε = 1.810 – 1.820
Birefringence	δ = 0.010
References	[2][3][4]

Cerite was first described in 1803 for an occurrence in Bastnäs in Västmanland, Sweden.^[4] The lanthanum rich species, cerite-(La) was first described for an occurrence in the Khibina massif, Kola Peninsula, Russia in 2002.^[7]

See also

• Earth sciences portal

• Classification of minerals
• List of minerals