I hiked the BMT from the Ocoee powerhouse to the Hiawassee powerhouse this weekend. About 4 miles of the hike was alongside Big Lost Creek in TN. The water was very clear and I noticed the creek bed is made with a pearlescent turquoise / aquamarine rock. It was really cool looking and I have not seen it anywhere else.
It appears gray in the picture but it really isn't.
Does anyone know the name of the rock or anything about it?