This is Peyto Lake, along the Icefields Parkway in Canada, between Banff National Park and Jasper National Park. The lake really is emerald-colored like this. It comes from **rock flour** which consists of fine-grained, silt-sized particles of rock from glacial erosion.  They suspend in the water and the refraction of light off of them causes the amazing color.

Peyto Lake
This is Peyto Lake, along the Icefields Parkway in Canada, between Banff National Park and Jasper National Park. The lake really is emerald-colored like this. It comes from **rock flour** which consists of fine-grained, silt-sized particles of rock from glacial erosion. They suspend in the water and the refraction of light off of them causes the amazing color.