| Cerite | |
|---|---|
Cerite – Bastnas – Deposit Topotype
| |
| General | |
| Category | Silicate mineral group |
| Formula (repeating unit) | (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 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 was first described in 1803 for an occurrence in BastnäsinVästmanland, Sweden.[4] The lanthanum rich species, cerite-(La) was first described for an occurrence in the Khibina massif, Kola Peninsula, Russia in 2002.[7]
Media related to Cerite-(Ce) at Wikimedia Commons
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