Fluorite

Unknown Owner

Beautifully iridescent sharp cubic lustrous crystals of fluorite measuring to 1.0 cm on edge across the top of matrix. In great condition. These iridescent fluorite crystals were never common at this particular locality.The White Rock Quarry near Clay Center, Ohio, is a limestone quarry that has produced a variety of mineral specimens from Silurian age carbonate rocks in the region. Quarrying operations exposed cavities and fractures where minerals such as fluorite formed from mineral rich fluids moving through the rock. Fluorite from this locality is especially noted for its iridescent surfaces, which display a range of shifting colors. This iridescence is not due to the internal color of the fluorite itself, but is caused by thin surface films or microscopic layers that create interference effects when light reflects from them. Variations in thickness of these films cause different wavelengths of light to be reinforced or canceled, producing the observed color play.