Activators in Fluorescent Minerals

Abstract

Why does calcite from Franklin, New Jersey, fluoresce red, calcite from elsewhere fluoresce white, green, or blue, while many other calcites do not fluoresce at all? In most cases, the fluorescence is caused by the presence in the mineral of an “activator.” An activator is usually thought of as a “foreign” element, sometimes present only in small amounts. When a mineral does not fluoresce, it may be because it does not contain a suitable activator. Of the somewhat more than 90 elements which occur in nature, only a few appear to be important as activators of fluorescence in minerals. These include manganese, uranium, some of the “rare earth” metals, and a few others.