Zinc sulfide (ZnS) is a relatively hard material and is resistant to thermal and mechanical shock. It is insoluble in water but can be attacked by strong acids and bases. ZnS is classed as a GRAS material. Its spectral range is more limited than ZnSe in the long wavelength region. Coated versions of our ZnS ATR crystals are available for improved IR throughput and enhanced seal within the ATR crystal plate.