Analcime-bearing tuffs from Bosnia and Herzegovina: mineralogy and structure data

The mineralogical and structural properties of the analcime-bearing rocks from Milići (Bosnia and Herzegovina) have been investigated in this work. The analyzed tuff samples, enriched in natural analcime, were characterized through microscopic, DTA/TGA, SEM, and X-ray powder diffraction analysis. The mineralogical composition of the analcime-bearing rocks consists of analcime, quartz, feldspars, mica, carbonates, volcanic glass, zircon, apatite, rutile, and plant fossils. Quantitative XRD analysis shows that the most abundant mineral is analcime. The representative composite sample of analcime-bearing rocks was refined on tetragonal (I41/acd) unit-cell parameters. Tetragonal unit-cell parameters of analcime yielded the best refinement agreement factors ( a = 13.7097 (3), c = 13.6953 (4) Å, V = 2571.32 (5) Ǻ3 – Rw = 14.2, Rp = 12.2, Rexp = 8.7, DW stat. = 1.1, GofF = 1.6). The quantitative amounts of main minerals obtained using the Rietveld method yielded before the following results (wt %): analcime 48.79% ( RB = 5.99, RF = 5.95), sanidine 29.20% ( RB = 2.55, RF = 2.31), biotite 15.99% ( RB = 6.56, RF = 3.94), quartz 6.02% ( RB = 4.86, RF = 4.63).