King of Arizona Mine, Kofa Mining District, Yuma County, Arizona, USA
Botryoidal opal-AN coated with calcite. Former Don Miller collection.
© 2019 Harold Moritz
White calcite coating botryoidal opal-AN. Former Don Miller collection.
Blue-white fluorescence (uncertain of the mineral) associated with pale green fluorescing chalcedony and very faintly fluorescing calcite. Former Don Miller collection.
Botryoidal opal-AN coated with calcite. The bright green fluorescence of the opal under SW UV light is illuminating the non-fluorescent calcite. Former Don Miller collection.
Drusy brown calcite with drusy quartz and chalcedony. Former Don Miller collection.
Botryoidal opal-AN fluorescing bright green under SW UV light. Associated calcite is not fluorescent, the color refracts through and illuminates it. Former Don Miller collection.