Eudialyte

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.