Eudialyte


Also found in: Dictionary, Wikipedia.

Eudialyte

 

a mineral; a zirconium silicate with the chemical composition Na2 Ca6 Fe3 Zr3[Si3O9]2 [Si9O24 (OH)3]2. Eudialyte contains 12–14.5 percent ZrO2 and admixtures of rare-earth elements (up to 7 percent TR2O3). It crystallizes in the trigonal system, forming lamellar, prismatic, and rhombohedral crystals. It usually occurs in the form of granular masses. It is raspberry red, pink, brown, or yellow and has an imperfect cleavage and a vitreous luster. Its hardness on Mohs’ scale is 5, and its density is 2,600–3,190 kg/m3.

Eudialyte fuses easily and dissolves in acids. It is found in nepheline syenites, syenitic pegmatites, albite-aegerine metasomites, and other rocks. It occurs on the Kola Peninsula and in Scandinavia, Tuva, Krasnoiarsk Krai, the Saian Mountains, Canada, and elsewhere. When it occurs in significant accumulations, eudialyte is a source of zirconium.

References in periodicals archive ?
Elongated nepheline crystals pointing downward form brush-like crusts, with eudialyte grains and dark green aegirine aggregates between the nepheline crystals.
2000) Kentbrooksite, ferrokentbrooksite and eudialyte from Pocos de Caldas, Minas Gerais.
2]O, two new eudialyte group minerals from Dara-i-Pioz alkaline massif, Tajikistan.
Fortunately, the specimen itself was a tough one (a eudialyte crystal half embedded in matrix) and suffered no direct damage.
As an example of how strange these Lovozero "pegmatites" can be, one of them, which Pekov calls "the narsarsukite occurrence," has a groundmass composed of albite, aegirine, lorenzenite, eudialyte and neptunite, with veins of massive narsarsukite up to 2 meters thick.
In addit ion there were Scandinavian classics like loose, sharp 2-cm pyritohedrons of cobaltite and sharp, lustrous pseudo-octahedrons of glaucodot from Sweden; well crystallized leucophanite, columbite and thortveitite from Norway; and richly brownish red, euhedral crystals of eudialyte to 2 cm in complex ultra-alkaline matrix, not from the Kola Peninsula, Russia, but from 19th-century localities in Greenland.
Associated minerals are: aegirine, albite, analcime, ancylite-(Ce), calcite, catapleiite, dawsonite, donnayite-(Y), elpidite, epididymite, eudialyte, eudidymite, fluorite, franconite, gaidonnayite, galena, genthelvite, gmelinite, gonnardite, horvathie-(Y), kupletskite, leifite, microcline, molybdenite, narsarsukite, natrolite, nenadkevichite, petersenite-(Ce), polylithionite, pyrochlore, quartz, rhodochrosite, rutile, sabinaite, serandite, siderite, sphalerite, thomasclarkite-(Y), zircon and an unidentified Na-REE-carbonate (UK91).
Associated minerals are: labuntsovite, natrolite, calciohilairite, aegirine, eudialyte, lorenzenite, murmanite, potassic feldspar, etc.
The following minerals are found in the nepheline syenites: britholite, titanite, eudialyte, lamprophyllite, and apatite.
Relationship to other species: A member of the eudialyte group, specifically the iron-dominant analogue of manganokhomyakovite.
He was the first to describe the geology of Mont Saint-Hilaire and the first to report eudialyte and other rare, peralkaline minerals at this locality.
Associated minerals are: quartz, microcline, albite, aegirine, polylithionite, reedmergnerite, sogdianite, pyrochlore, eudialyte, and turkestanite.