This is the yellowish-gray fluorite sphere. Diameter 2.6″ (67mm). Weight – 17.5oz (497 grams). Origin: Russia, Transbaikalia.
Some information about fluorite:
Fluorite (also called fluorspar) is a halide mineral composed of calcium fluoride, CaF2. It is an isometric mineral with a cubic habit, though octahedral and more complex isometric forms are not uncommon.
Fluorite comes in a wide range of colors and has subsequently been dubbed «the most colorful mineral in the world». The most common colors are purple, blue, green, yellow, or colorless. Less common are pink, red, white, brown, black, and nearly every shade in between. Color zoning or banding is commonly present. The color of the fluorite is determined by factors including impurities, exposure to radiation, and the size of the color centers.
Fluorite derives from the Latin noun fluo, meaning a stream or flow of water. In verb form this was fluor or fluere, meaning to flow. Fluorite crystallises in a cubic motif. Crystal twinning is common and adds complexity to the observed crystal habits.
Fluorite is a widely occurring mineral which is found in large deposits in many areas. In Russia the largest fluorite deposits located in the Transbaikalia (Chita region, deposits in Buryatia).