Polarized microscopes illuminated samples with polarized light or directly transmitted light that is blocked with a polarizer orientated at 90 degrees to the illumination. Microscopy techniques which take advantage of polarized light include differential interference contrast microscopy and interference reflection microscopy. Some applications that involve polarization include geological studies to highlight features of minerals, forensic investigations of trace evidence based on the distinctive appearances of different materials under the polarized illumination, and the quantitative measurement of optical properties of biological specimens without exogenous stains. Look for powerful microscope optics, ergonomic design, a range of objectives, and robust, vibration resistant construction.