A method of detecting one or more scratches on a surface of a wafer made of a non-semiconductor material is provided. A UV beam is produced from a UV illumination source. The UV beam is incident on a front surface of the wafer. The UV beam being characterized that for scratches of a given material having a UV cutoff wavelength .lamda..sub.cutoff, over 90% of the spectral system response SSR is at wavelengths below .mu..sub.cutoff-5 nm and expressed as:.intg..lamda..times..times..function..lamda.>.intg..infin..times..f- unction..lamda. ##EQU00001## A reflected beam of scattering of the UV beam is detected in response to scratches on a surface of the wafer. The scattering is captured.