A quite special circular arrangement of diatoms from St Peter, Hungary. Minor movement of some of the diatoms. Some yellowing of the mountant. Prepared by Watson and Sons Ltd. Olympus BHB microscope using white LED light. 4x Nikon Plan Apo NA 0.20 objective. Olympus Aplanat Achromat condenser, brightfield lighting. 2.5x Nikon CF PL photoeyepiece. Canon EOS 5 DSR camera. Single unstacked image.