Yooperlite

Yooperlites are a type of syenite rock rich in sodalite, primarily found washed up along the shores of Lake Superior, especially in Michigan's Upper Peninsula after big storms. Yooperlites were discovered by Erik Rintamaki in 2017 and named after Michigan's Upper Peninsula nickname, "Yupers". 

Yupers commonly refer to everyone else not from the area as “Trolls”.  These rocks glow orange or yellow under UV light due to the fluorescence of the sodalite.

Yooperlite stones have a Mohs Hardness of only 5-6.