Britholite-(Ce)
Britholite-(Ce) is a rare earth cerium-dominant nesosilicate mineral with the chemical formula (Ce,Ca,La,...)5(SiO4,PO4)3(OH,F). It is a member of the apatite group. Britholite-(Ce) is typically found in alkaline igneous rocks and carbonatites.
Properties:
- Color: Commonly yellowish-brown, reddish-brown, or gray.
- Luster: Vitreous to greasy.
- Crystal System: Hexagonal.
- Hardness: 5-6 on the Mohs scale.
- Density: 4.3 - 4.6 g/cm3.
- Cleavage: Indistinct.
- Fracture: Conchoidal to uneven.
- Streak: White.
- Optical Properties: Uniaxial (+).
Occurrence:
Britholite-(Ce) is found in various geological settings, including:
- Alkaline igneous rocks such as nepheline syenites and phonolites.
- Carbonatites.
- Pegmatites.
- Metamorphic rocks.
Identification:
Britholite-(Ce) can be identified by its color, luster, hardness, density, and association with specific rock types. X-ray diffraction and electron microprobe analysis are often used for definitive identification. Its radioactivity due to the presence of thorium and uranium may also aid in identification, but caution is advised.
Etymology and Nomenclature:
The name "Britholite" is derived from the Greek words "brithos" meaning "heavy" and "lithos" meaning "stone," referring to its relatively high density. The suffix "-(Ce)" indicates that cerium (Ce) is the dominant rare earth element in the mineral's composition. Other varieties with different dominant rare earth elements exist, leading to different suffixes.
Significance:
Britholite-(Ce) and other rare earth element-bearing minerals are important sources of these valuable elements, which are used in a wide range of technological applications, including electronics, magnets, and catalysts. Its presence can be an indicator of potentially valuable rare earth element deposits.