Loparite-(Ce)

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Loparite-(Ce)
Loparite-(Ce)-41714.jpg
General
CategoryOxide minerals
Formula
(repeating unit)
(Ce,Na,Ca)(Ti,Nb)O3
Strunz classification4.CC.35
Crystal systemLoparit-(Ce)-Q: tetragonal[1]
Loparit-(Ce)-O: orthorhombisch[1]
Loparit-(Ce)-C: cubic[2]
Identification
ColorBlack to grey-brown in thin section
Crystal habitCubic and octahedral crystals and massive
TwinningPenetration twins common on [111]
Cleavage[100] Imperfect
Fractureuneven
TenacityBrittle
Mohs scale hardness5.5 - 6.0
LusterMetallic to sub-metallic
Streakreddish brown
Diaphaneityopaque, transparent in thin fragments
Specific gravity4.60-4.89
Optical propertiesIsotropic, anomalously anisotropic
Refractive indexn = 2.26–2.38
References[3]

Loparite-(Ce) is a granular, brittle oxide mineral of the perovskite class. It is black to dark grey and may appear grey to white in reflected light on polished thin section with reddish brown internal reflections.[4] It has the chemical formula of (Ce,Na,Ca)(Ti,Nb)O3.[3] Nioboloparite is a variation of Loparite-(Ce) containing niobium.[5]

Loparite occurs as a primary phase in nepheline syenite intrusios and pegmatites. It is also found replacing perovskite in carbonatites.[3]

Loparite was first described for an occurrence in the Khibiny and Lovozero massifs, Kola peninsula and northern Russia.

Etymology[edit]

The term originates from the word Lopar, the Russian name for the Sami indigenous inhabitants of the Kola peninsula, and the cerium content.[3][4][5]

Notes[edit]

  1. ^ a b Mitchell R H, Burns P C, Chakhmouradian A R (2000) The crystal structures of loparite-(Ce), The Canadian Mineralogist 38, 145-152.
  2. ^ Zubkova, N. V., Arakcheeva, A. V., Pushcharovskii, D. Y., Semenov, E. I., & Atencio, D. (2000). Crystal structure of loparite. Crystallography Reports, 45(2), 210-214.
  3. ^ a b c d "Loparite-(Ce)" (PDF). Mineral Handbook. Mineral Data Publishing. 2005. Retrieved 2008-07-19.
  4. ^ a b Loparite-(Ce) on Webmineral
  5. ^ a b Loparite-(Ce) on Mindat.org

External links[edit]