Fluorite is one of the most varied colored minerals in the mineral kingdom, which probably explains why it is one of the most popular! This mineral serves as the reference mineral for a hardness of 4 on the Mohs Hardness Scale, making it too soft for everyday wear as a gem, though it is carved into wonderful faceted stones and sold as collector's specimens or used in jewelry that is not subject to impact or abrasion. Fluorite is also popular for its interesting cleavage habits, many times creating some perfect octahedrons. Last but not least, Fluorite is one of the more famous fluorescent minerals. Many specimens strongly fluoresce, in a great variation of color. In fact, the word "fluorescent" is derived from the mineral Fluorite.