It has been investigated the photoluminescence and X-Ray diffraction spectra of ZnS : Mn microcrystals (dimension ~ 25 μm). After mechanical crush (time 10 and 20 min) the physical properties of microcrystals was changed. Dimension of micro crystals decrease up to 10 μm (mechanical crush 10 min) and 5 μm (mechanical crush 20 min); intensity of photoluminescence decrease too at 6,5 and 10 times accordingly. The paper will present the physical reasons of this result.