Rockhounding in Indiana – What Rocks You Can Find and Where

Fluorite

Hardness: 4

Streak: White

Chemical Formula: CaF₂

Composed of Calcium and Flourine, Fluorite is a very popular mineral. It commonly occurs as well-formed, colorful crystals. Pure fluorite is colorless, but various impurities cause the wide spectrum of colors that fluorite crystals are known for.

Fluorite is also well-known for its ability for some specimens to fluoresce under ultraviolet light. Even their fluorescent colors can vary from blue to a white or cream color.

Fluorite is created by hydrothermal processes as an accessory mineral in silica-rich rocks. It is often found in veins containing metallic ores such as sulfides of tin, lead, zinc, and copper.

Fluorite has a wide variety of uses today and is referred to as Fluorspar when sold as a bulk material. Fluorite is used in manufacturing hydrofluoric acid, ceramics, and as flux for removing impurities in metal production.

Fluorite can also be a beautiful gemstone when faceted, but because of it’s relatively low hardness of 4 it is not commonly used.