Radiocesium (RCs)-carrying materials derived from the Fukushima nuclear accident consist of RCs-sorbing minerals (CsSMs) and RCs-bearing silicate-glass microparticles (CsMPs). We reveal that while acid treatment has little effect on CsMPs, it significantly decreases the radioactivity of CsSMs due to dissolution. Using this difference, we propose a novel approach to estimating the contributions of CsMPs and CsSMs to total radioactivity of contaminated materials using autoradiography or gamma-ray spectroscopy. Distribution of CsMPs in samples can also be elucidated without time-consuming microscopic analysis.