Green Fluorite

Hardness: 4 (Mohs scale), Color: Pale to mint green, Luster: Vitreous, Crystal structure: Cubic (though this specimen is tumbled/polished), Cleavage: Perfect octahedral, Specific gravity: 3.175–3.184

Fluorite forms in hydrothermal veins, often associated with metallic ores. It crystallizes from hot mineral-rich fluids escaping from cooling magma through fissures in sedimentary rocks (mostly limestones) or igneous rocks. Most deposits range from the Paleozoic to the Cenozoic era.

Industrial uses include flux for steel smelting, production of hydrofluoric acid, and high-clarity lenses for telescopes and cameras. Common in jewelry (beads/rehearsal stones) and popular for metaphysical collecting.

Fluorite is often called 'the most colorful mineral in the world'. It gives its name to the phenomenon of fluorescence because many specimens glow blue or violet under ultraviolet light. It is the official state mineral of Illinois.

Identify by its relatively low hardness (can be scratched by a steel knife) and its habit of glowing under UV light. It is commonly found in China, Mexico, South Africa, and the USA (Kentucky and Illinois). Collectors look for transparency and rich saturation of color.