Calcite, modified scalenohedrons with dark marcasite inclusions. Linwood Mine, Buffalo, Scott County, Iowa, USA. Under long wave UV (365nm) probable organic inclusions, visible as tan regions near the base of the crystals under visible light, fluoresce white. Under short wave UV (254nm) the organic inclusions again show a white response, accompanied by pastel pink fluorescence more evenly distributed though the crystals, possibly due to manganese/lead activation. FOV: 4.9 x 3.3 cm