UPPER PENINSULA (WWJ) -- A bright, blue mineral has been discovered in Michigan's Upper Peninsula and people are wondering what it could possibly be...
The mysterious mineral was found on rock walls in the historic U.P. Adventure copper mine in Greenland Township, south of Lake Superior.
On Sunday, officials from the mine have posted pictures on Facebook of the mystery substance found on rock walls, but the bright blue material has not been positively identified.
Officials said they believe it to be a secondary mineral caused by a reaction with air and water.
The mine operated from 1850 until 1920 and 11 million lbs. of native copper has been extracted.