A cut, but unpolished, Lava Cap Thunder Egg half, containing chalcedony, calcite and manganese oxide pseudomorphs, enclosed in a rhyolite shell. There are also areas of aragonite coverage on the exterior of the rhyolitic shell. Under SW UV, the chalcedony fluoresces bright green and the calcite red. The aragonite shows a blue/white response with phosphorescence. This specimen measures 47 x 42 x 20 mm. These beautifully fluorescent thunder eggs occur on the Coleman Claim, Florida Mountains, Deming, New Mexico.
