What Are Fluorescent Rocks?

Causes

• Impurities, called activators, found in a mineral may cause fluorescence. Different minerals may require different impurities to create the reaction. The type and amount of activator present in the mineral will affect the color and the degree of fluorescence.

UV Light

• There are some minerals that will only fluoresce under long wave UV radiation. These minerals will glow under a black light and are frequently on display. Some fluorescent minerals will fluoresce only under short-wave UV radiation or UV-B light.

Common Fluorescent Minerals

• Calcite will glow red, yellow, pink or blue when under a black light. Willemite will glow bright green under UV-B light. Fluorite will glow blue under a black light. Scheelite will glow a blue-white under UV-B light.

Location

• The activator elements will often come from surrounding rocks. Therefore, fluorescent minerals may be specific to a location. Franklin, New Jersey, is known as the fluorescent capitol of the world with more than 56 fluorescent minerals mined there.

Self-activated Fluorescent Minerals

• Minerals, such as schellite and powellite and those containing uranium, are considered to be self-activated; they do not need an impurity to be fluorescent. These minerals consistently fluoresce.