Yooperlites
These strange glowing stones are becoming quite the attraction for local and visiting rock hunters.
Popularized in 2017, yooperlites are made of mostly syenite rock, similar to granite, which means the rock looks like any other typical gray rock. The twist is that Yooperlites are rich with fluorescent sodalite, which glows a vibrant orange or yellow under ultraviolet (UV) light.
The glow-in-the-dark deposits of sodalite can form various patterns, including sparsely spotted, geometric lines, or an all-over pattern. The fluorescent material in these syenites had been visually identified as sodalite by California geologist and fluorescent mineral collector Gabe Reyna.
Yooperlites, as the name suggests, are found in Michigan’s Upper Peninsula, specifically along the Lake Superior coast from the Keweenaw Peninsula to Sault Ste. Marie.
Today, there are about 383 minerals known in Michigan, however, recent finds like the fluorescent sodalite suggest that the mineralogy of our state is significantly understudied and that many new minerals may await discovery here.
If you want to head out in the evening and search for yooperlites you’ll need a black light UV flashlight. Without a UV light, the rocks won’t glow so a good quality UV light is a must! A filtered UV flashlight with UV 365nm works best for maximum visibility.
Happy rock hunting!
Yooperlites found in June 2022. Photo by Craig Shawgo.
‘Yooperlite’ is a trademarked brand by Erik Rintamaki.
Note: Some areas are restricted for rock hunting. It is illegal to remove anything from any National Park or Lakeshore.