A strew slide of Pleurosigma angulatum. Prepared by Johann Diedrich Möller. Unusual rainbow pattern seen from the slide under white light illumination. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo NA 1.40 obejctive, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, slightly oblique lighting. 2.5x Nikon CF PL photoeyepiece. Removed 11mm from the extension tube to increase field of view and fit the diatom in. Monochrome converted Nikon d850 camera. 7 images stacked in Zerene (Pmax).