Fluorite (also called fluorspar) is a mineral consisting of calcium fluoride, CaF2. It belongs to the halide minerals, alongside common salt (called halite in its mineral form). Halide minerals crystalize in the cubic (isometric) system, which means that its crystals are basically a cubic motif. Crystal twinning is common and adds complexity to the observed crystals. Its cleavage is perfect, as can be seen in this picture.
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