Here I loved the contrast of the rock color with the green and red and an occasional brown rock. The colors of Glacier National Park.

"Then there is light green or burgundy argillite of Appekunny formation. Both versions have the same iron content, but the purple version is more oxidized. It was deposited closer to shore than Altyn. The Grinnell formation is the one dominated by burgundy argillite. The Empire formation is a transitional formation between Grinnell and Helena. Helena consists of medium to dark gray dolostone and limestone, often covered with honey-colored weathering rind." https://blogs.agu.org/mountainbeltway/2 ... onal-park/