Loparite-(Ce) is a granular, brittle oxide mineral of the perovskite class. It is a brown to black mineral; a variety of perovskite containing alkalies and cerium. It has the chemical formula of (Ce, Na, Ca) (Ti, Nb)O3. Nioboloparite is a variation of Loparite-(Ce) containing niobium. Loparite concentrate is refined by either a chlorination process or acid decomposition process to recover rare-earths, titanium, niobium, and tantalum.
Loparite was first described for an occurrence in the Khibiny and Lovozero massifs, Kola peninsula and northern Russia.
General Information
- Category: Oxide minerals
- Formula: (Ce, Na, Ca) (Ti, Nb) O3
- Crystal system: Loparit-(Ce)-Q: tetragonal, Loparit-(Ce)-O: orthorhombic, Loparit-(Ce)-C: cubic
- Color: Black to grey-brown in thin section.
Properties
It is black to dark grey and may appear grey to white in reflected light on a polished thin section with reddish-brown internal reflections.
- Crystal habit: Cubic and octahedral crystals and massive
- Twinning: Penetration twins common on [111]
- Cleavage: [100] Imperfect
- Fracture: uneven
- Tenacity: Brittle
- Mohs scale hardness: 5.5 – 6.0
- Luster: Metallic to sub-metallic
- Streak: reddish-brown
- Diaphaneity: opaque, transparent in thin fragments
- Specific gravity: 4.60-4.89.
Occurrence: A primary phase in differentiated nepheline syenite massifs and alkalic pegmatites; replacing perovskite in carbonatites.
Loparite occurs as a primary phase in nepheline syenite intrusions and pegmatites. It is also found replacing perovskite in carbonatites.
Association: Nepheline, microcline, aegirine, rare-earth-bearing apatite, arfvedsonite, perovskite, ilmenite, eudialite–eucolite, titanite, lamprophyllite.
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