What exactly are fluorescent minerals? This is a very common question by anybody who has never seen a rock glow and change color. Many believe the rocks are painted on or some other trick is being done to create this magical effect. But mother nature is the source of these magical beautiful rocks! They can be found all other the world and in every state in the USA. The observation of rocks changing color can date back thousands of years but its only been within the last 75 years we have had tools that can allow us to clearly see what fluorescent minerals look like.
All fluorescent rocks need some type of external energy for them to produce the color change. Its also best to see them in the dark. The reason for this is because visible light masks the fluorescent response created by the rock. To best simply explain what exactly is going on is fluorescent minerals absorb radiation energy and that absorption is released back from the rock in the form of color. Over 90% of the rock species that will change color need shortwave ultraviolet radiation or energy below that in order to respond. The most common form of lights are commonly known as blacklights but black lights do not produce the right amount of UV energy to produce the color response. Shortwave UV bulbs with special external optical filters produce the desired color change. The special optical filter blocks the visible light generated by the bulb and allows the shortwave UV to pass onto the rock. This optical filter is also the main reason why shortwave UV lights are so expensive. A lot of people try to save money by purchasing a blacklight but quickly realize that they just will not work.
Fluorescent minerals typically have some type of impurity in them that allows them to glow. These are referred as activators and manganese is a common activator in fluorescent minerals. Even diamonds can be fluorescent because of other mineral impurities in them which cause them to glow. Another common question about fluorescent minerals are do metals glow such as gold, silver, iron, copper, etc.? And the answer is no all metals are not fluorescent even is other minerals in the metal are present. But several mines such as gold and silver mines do have minerals around that are fluorescent. If a prospector is hunting for a outcrop and finds fluorescent minerals it stands to have a good change some other type of valuable mineral is present. Examples of such are gold, silver, zinc, and scheelite.