Calcite and chalcedony, fluorescent red and green under UV light, respectively. The calcite is between two layers of chalcedony, giving the appearance of a watermelon slice. Usually these are photographed from their side, showing a cross cut of the three layers. In this case, the front chalcedony layer is broken, showing some of the calcite. The appearance of a watermelon rock is lost, but easier to display. The calcite reacts best under midwave UV light, while the chalcedony is quite good under both mid and short wave UV.
Fluorescence under midwave and shortwave UV light.
Normal light.
Label from Bill Gardner.
