MINERALOGICAL CHARACTERISATION OF TITANITE FROM ALINCI, REPUBLIC OF MACEDONIA

Abstract

In this paper is presented the mineralogical characterization of titanite from Alinci, Republic of Macedonia. Two samples of titanite were analysed by scanning electron microscope (SEM) and XRD method. Titanite grows within arfvedsonite nests. Their growth started after the arfvedsonite had been crystallised. Мost commonly appear as (100) twins with a typical shape of steep roof. Titanite has honey yellow colour because has low concentration of Fe. The concentration of elements in titanite crystals is: Si (11.21-11.90); Ca (9.93-11.64); Ti (11.49-13.53), Fe (0.26-0.41). Arfvedsonite has black colour. The concentration of elements in arfvedsonite crystals is: Si (22,37-23,84); Fe (8.27-10.48); Ca (1,45-2,66); Mg (7.64-7.98); K(0.53-0.64); Na (3.73-4.34). The most intense registered maxima in the studied powder pattern [d values (in Å, I and hkl)] are: 3.24 (100); 3.00(87); 2.61(57); 2.59(41); 2.06(21); 2.29(19); 1.64(45); 1.55 (13); 1.50(15); 1.42(16). The most intense registered maxima in the studied powder diagram were compared with the corresponding maxima in the diagram of titanite sample ICDD card 00 050 1614 for titanite and ICDD 01 089 7346 for arfvedsonite. The results of the SEM analysis and X-ray powder pattern enable straightforward identification of the studied mineral samples as titanite in which small crystals of arfvedsonite were incorporated.

Key words: titanite, arfvedsonite, (SEM) - scaning electron microscope, (X-ray) - powder diffraction.