In the last few years, many nonmetallic minerals, including vermiculite, have been subject to geologic and mineral processing investigation in Yugoslavia. In this study, the identification of vermiculite from the Kusici–Kopaonik deposit (Yugoslavia) was carried out using microscopy, DTA, TGA, X-ray and IR spectroscopy methods. In addition, small amount of chlorite was identified in the examined sample by X-ray method. Expanding properties of different size fraction of vermiculite was performed, followed by the use of stereomicroscope and by measurement of the volumetric mass before and after the expansion. The maximum expansion was accomplished at 910– 920 °C. The IR spectra showed that heating of vermiculite at this temperature (about 900 °C), for only 7 minutes, resulted in notable reduction of absorption bands characteristics for water, indicating the important water loss from the mineral.