Glowing Minerals Are a Fascinating Find for Colorado Rockhounds
Colorado's diverse geology makes it an epic place to prospect, rockhound, and hunt for semi-precious stones and minerals. People enjoy rock hunting as a hobby and collecting personal samples throughout the wilderness and national forests of Colorado. Some of the popular areas to do so include Central City, Idaho Springs, and Boulder County.
All kinds of rocks and stones are found in the Centennial State, but some of the most unique specimens to uncover are fluorescent minerals. From the exterior, these appear like most other rocks, but when lit up with a UV lamp, they will actually glow in the dark.
In Colorado, glowing minerals oftentimes contain uranium. In addition to uranium ores, fluorescent (LW) sphalerite and fluorite are also present within the state.
In 2017, a fluorite specimen was found in the Fourmile Creek area, near Canon City. This was a rare discovery, in that the mineral displayed a bright green response under short wave UV. Usually, fluorite shows a deep, intense blue luminescence, green is not a common color for this mineral. This particular specimen was measured, tested for uranium, and confirmed to be radioactive.
Colorado's abandoned mines are a hot spot for fluorescent minerals. In 2020, a beautiful glowing specimen containing fluorescent sphalerite and fluorite was recovered from the Sweet Home Mine in Alma.
The same mineral hunter who found the specimen above also located some red fluorescent barite in Custer County, Colorado. The red was an atypical fluorescence - according to rock experts, most fluorescent barite responds to UV with pale white, blue/white, or cream/white fluorescence.
These glowing green rocks found in Leadville look like they were left here by aliens. In actuality, the uranyl ion is the cause of the bright green fluorescence.
Another rockhound discovered glowing zircon fluorite in Arvada.
A Colorado resident documented one of his fluorescent mineral prospecting adventures on YouTube. He set out during the nighttime in the central mining district in Boulder County.
Individuals wanting to search for fluorescent rocks and minerals should always explore the area they plan to hunt in during the daytime first. Besides getting familiar with the region, it's a smart idea to go with a partner or someone who is confident in Colorado's backcountry. Be sure to check that it's legal to take rocks and minerals from the land too. In national monuments, certain wilderness areas, and other special or protected areas, collecting may not be allowed.
Essential tools to bring along are a portable ultraviolet lamp, LED flashlight, a rock hammer, gloves for safely handling radioactive material, UV protective glasses, and a Geiger counter, which is an instrument used to detect radiation.