Green Fluorite on Sphalerite & Geocronite
Milpo mine, Atacocha mining dist,
Cerro de Pasco, Pasco prov, Pasco, Peru
8.5 cm wide x 6 cm tall
Intense green fluorites from Peru began appearing on the market 2 years ago. They are remarkably different in color and form than we have seen in the past. They are specific to this mine. From the examples we have observed there is a great variation in color; from pale lime green to emerald green and even some with a bluish green like a Zambian Emerald color.
This one is of the emerald green variety. It showcases a large, geometrically truncated octahedral crystal, highly transparent, having textbook-like shape, rendered in a vibrant green hue. The single isolated crystal is completely three dimensional. It sits atop a contrasting dark matrix of sphalerite and geocronite (geocronite is an unusual sulfide that often accompanies sphalerite.) The sharp clean edges of the crystal create a vivid contrast with the textured rougher crystallization of the matrix. This is one of the finest examples we have yet encountered.
Fluorite can exhibit fluorescence under ultraviolet light, a property that actually gets its name from fluorite. The fluorescence of fluorite can be due to mineral impurities, or organic matter inclusions.
The color of visible light emitted when a sample of fluorite is fluorescing often depends on where the original specimen was collected; different impurities having been included in the crystal lattice in different places. Not all fluorites fluoresce equally brightly, even from the same locality.
This green fluorite alters to a deep rich blue under UV spectrum lighting. Blue fluorescence has been attributed to the presence of inclusions of the rare earth mineral europium.