LITHIUM IN THE SUBSOIL OF UKRAINE Part 5. Mineralogy of lithium-bearing objects: lithium minerals

Abstract

The fifth part of the publication "Lithium in the depths of Ukraine" is devoted to the mineralogy of lithium — silicates and phosphates, but without lithium micas, which, together with other micas, are described in Part 4. Here, the following lithium minerals are characterized in varying detail (the Li2O content of the mineral (mas. %) is given in parentheses after the formula): eucryptite — LiAl[SiO4] (11.80), elbaite Na(Al,Li)3Al6(BO3)3(F,OH)4[Si6O18] (1.1—1.4); spodumene — LiAl[Si2O6] (5.9—7.6); holmquistite Li3Mg3Al2(OH)2[Si8O22] (2.1—3.5); petalite — Li[AlSi4O10] (2.0—4.1); margarite — CaAl2(OH)2[Si2Al2O10]-(Li,Be) (1.82); donbasite — Al2[(Si3Al)O10](OH)2·Al2.33(OH)6 (0.1—3.0); cukeite (Al,Li)3Al2[(Si,,Al)4O10](OH)8 (0.8—4.3); triphillite — Li(Fe2+,Mn2+)[PO4] (5.51—8.62); lithiophyllite — Li(Mn2+,Fe2+)[PO4] (5.50—8.60); amblygonite LiAl(F)[PO4] (6.4—9.0); montebrasite — LiAl(OH)[PO4] (10.7—11.1); simferite — Li(Mg,Fe3+,Mn3+)2.0[PO4] (5.35—5.45). The description of these minerals is supplemented by a summary table of the mineral composition of rare metal pegmatites, selected according to the quantitative ratio of the main ore minerals — spodumene and petalite. The latter are not the first phases of crystallization of the pegmatite melt, so their distribution in space is close to the following pattern: the highest content of ore minerals is concentrated between the peripheral zones and cores of pegmatites. Spodumene and petalite of Ukrainian pegmatites, in comparison with similar minerals of large global lithium deposits, differ in the following features: 1) smaller sizes of mineral individuals; 2) greater xenomorphism of mineral individuals; 3) a weaker manifestation of isomorphic substitutions of atoms.