Fluorite
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Fluorite is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncomm
The structure of calcium fluoride CaF2.
A closeup of fluorite surface
Blue Fluorite, from Shihe District, Henan Province, China
Sphalerite
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Sphalerite is a sulfide mineral with the chemical formula S. It is the most important ore of zinc. Sphalerite is found in a variety of deposit types, but it is primarily in sedimentary exhalative, Mis
Black crystals of sphalerite with minor chalcopyrite and calcite
Sphalerite fluorescing under ultraviolet light (Sternberg Museum of Natural History, Kansas, US)
Faceted sphalerite, known by the name of Étoile des Asturies, one of the largest in existence. It actually comes from the Aliva mine, Cantabria (Spain). Cantonal Museum of Geology of Lausanne.
Sphalerite and barite from Cumberland Mine, Tennessee, US