Loparite

loparite

[′lō·pə‚rīt]
(mineralogy)
(Ce,Na,Ca)2(Ti,Nb)2O6 A brown to black mineral; a variety of perovskite containing alkalies and cerium.

Loparite

 

a mineral of chemical composition (Na, Ce, Ca)2-(Ti, Nb)2O6. The principal admixtures are Sr, Y, and Th. Loparite crystallizes in the isometric system, forming primarily small (up to 2-3 mm) crystals, which generally occur as penetration twins. Loparite is structurally similar to perovskite and exhibits no cleavage. It is black, opaque, and has a semimetallic luster. Its hardness is 5.5-6, and its density 4,750-4,890 kg/m3. Loparite occurs in nepheline syenites (sometimes as one of the rock-forming magmatic minerals) and, more rarely, in pegmatites genetically related to nepheline syenites.

References in periodicals archive ?
In reality, with the exception of promethium (which has no long-lived isotopes and, according to the US Geological Survey, occurs naturally only in 'vanishingly small' quantities), rare earths are generally found in fairly high concentrations in four minerals--bastnasite, loparite, monazite and xenotime--along with rare-earth ionadsorption clays.
So, loparite concentrate, produced in processing of the Lovozero deposit ores, contains 0.6 % TiO2, while Irshansky ilmenite from Ukraine--57.0-59.5 % [3].
As a logical sequel to dictyonema shale processing, work with enriched uranium [sup.235]U power reactor fuel and the thorium-rich loparite from Kola Peninsula [1] followed.
The Palitra pegmatite, recently discovered during underground mining operations at a loparite deposit in the Lovozero massif, is one of the most interesting mineral localities within this famous alkaline complex.
The plant, however, suspended its rare metals production in the second half of 1998 owing to problems with supplies of loparite concentrate from the Sevredmet mine (Murmansk region).
Altogether 152 379 metric tons of Lovozero loparite 90 [+ or -] 5% concentrate were brought to the Oil Shale Processing Plant and fully used during the years 1970 to 1991.
Selsurt) loparite with average composition ([Na.sub.0.45] [LREE.sub.0.35] [Ca.sub.0.14] [Sr.sub.0.04] [Fe.sub.0.005] [Th.sub.0.004])([Ti.sub.0.90] [Nb.sub.0.10] [Ta.sub.0.008])[O.sub.3] and average molecular weight of 172, classified as calcian niobian loparite-(Ce), is actually a solid solution of loparite ([Na.sub.0.5] [LREE.sub.0.5] Ti[O.sub.3]) with perovskite (CaTi[O.sub.3]) and tausonite (SrTi[O.sub.3]) in the thorium-substituted A-site and with lueshite (NaNb[O.sub.3]) in the tantalum-substituted B-site.
Associated minerals are: microcline, aegirine, arfvedsonite, nepheline, eudialyte, albite, lorenzenite, loparite, aenigmatite, manganneptunite, murmanite, analcime, natrolite, stilbite, chabazite, kuzmenkoite-Mn, nontronite, and others.
As the changes in the production profile will free manpower, the Head of the 3rd Main Technological Directorate and the Deputy Head of the Main Economical Directorate have to reconsider economic specifications of the Sillamae Chemical-Metallurgical PA to be engaged in development of machine building and production of consumer goods, and to guarantee the processing of loparite concentrate as well as to solve ecological problems.
243), has already shown him to be an encyclopedic authority on Russian and former-Soviet Union mineral occurrences once taboo to write about, The old, paranoid Soviet government, Pekov tells us, was always particularly touchy about Lovozero, since one of the massif's unique mineralogical features is a huge deposit of loparite (!) containing the world's largest reserves of tantalum, niobium, and rare-earth elements.
Giant deposits of apatite and loparite are currently being mined at the Khibiny complex.
Additional minerals included bright black loparite twins (to 8 mm) in aegirine-eudialyte syenite, and black veinlets (to 2 mm thick) of schneiderhohnite in muscovite from the Keivy pegmatite, Kola peninsula.