This is the mineral Fluorite. It has a vitreous luster, which means glassy, and produces a white streak. Pure Fluorite is colorless and composed of just 2 elements, Calcium and Fluorine. Since it’s composed of only 2 elements, and one of these elements, Fluorine, belongs to Group 17, also known as the Halogens, on the Periodic Table, Fluorite belongs to the Halide chemical family. Fluorite is a defining mineral on Mohs hardness scale, ranking number 4 and thus able to scratch Talc, Gypsum, and Calcite. It exhibits perfect octahedral cleavage, and thus a perfect Fluorite crystal has 8 faces and resembles two pyramids joined at their bases. Its specific gravity is between 3 and 3.3, making it feel neither heavy nor especially light in your hand. While pure Fluorite has no color, the most common variety is violet, owing to slight elemental impurities. Many other colors exist, including pastel green, golden yellow, dark burgundy, and teal. These colorful properties, coupled with its relatively low hardness rank, make Fluorite an especially sought after mineral for carving into appealing decorative shapes. Fluorite has numerous industrial applications. It’s especially important as a flux in smelting because it chemically combines with impurities in ore, resulting in a more refined product. It also decreases molten metal’s viscosity, thereby making it easier to handle and alloy with other compounds. Recall that the element Fluorine is 1 of the 2 elemental ingredients in the mineral. After separating Fluorine from Fluorite, it can be combined with Uranium to produce Uranium Hexafluoride, also called Hex, which is an essential compound used to enrich Uranium for power plants and nuclear weapons. Perhaps Fluorine’s most recognized use is when it’s combined with Sodium to create Sodium Fluoride. This compound is added to public water supplies to strengthen tooth enamel and is an essential ingredient in toothpaste. Next time you brush your teeth, examine the Active Ingredient on the toothpaste tube.