NEW DATA ON MINERALS WITH ECONOMIC POTENTIAL PRESENT IN LITHIUM PEGMATITES FROM CON?U � NEGOVANU, CIBIN (CINDREL) MOUNTAINS, CENTRAL GROUP, SOUTHERN CARPATHIANS, ROMANIA

Abstract

In this paper will discuss the minerals present in pegmatites, seen as a way of storing chemical elements, important from an economic point of view. The study area is called Con?u - Negovanu, and is located between the two mountain massifs known as Cindrel (Cibin) and Lotru Mountains. Muscovite (seen as a possible indicator for lithium in Con?u � Negovanu pegmatites), one of the important minerals alongside quartz, spodumene, and albite cleavelandite variety, is probably the mineral that includes in its structure chemical elements: Fe3+, Fe2+, Mg2+, Mn2+, Ti, Li, Nb, Ta, Sn, Ce, K, Na, Ca2+ which tend to materialize in minerals such as triphylite - lithiophilite, ferrisicklerite, heterosite - purpurite, amblygonite � montebrasite, "ferrogatehouseite", fluorapatite, hydroxylapatite, vivianite, wolfeite, maricite, monazite, cassiterite, titanite, spodumene, cookeite. In addition to these, we indicate beryl, scarce schorl, uraninite, garnets, kyanite, staurolite and columbite - group minerals. Phyllosilicates viewed through the mineralogical prism of pegmatites provide information on crystallization, mainly temperature (the presence of the 2M1 polytype indicates a high temperature) and the evolution pressure of pegmatitic melts. Plagioclase (oligoclase and albite) is partially or replaced by muscovite and quartz - a stable association in the later stages of pegmatites, following the crystallization of microcline by reducing the formation of muscovite, and if there is an increase in water content, the proportion changes, the microcline is partially or replaced of muscovite. Chemical analysis: EPMA indicates in muscovite the presence of FeO with an average value of 1.44 %, and Na2O with an average value of 0.44 %, fluorine occurs in proportions with values from 0.04 to 0.30 %.