As we float through the grand basement of time on the Colorado River in the Grand Canyon, the rock viewing along the river banks had changed to now start showing us some of the oldest history to be found in the canyon. The sandstone Tapeats layer starts to give way to the metamorphic shist layers of vishnu below.

For even more time-test beauty, the black Vishnu Schist is covered in erratic patterns of pink Zoroaster Granite. Zoroaster granite is classified as a coarse-grained pegmatite comprised of quartz, alkali-feldspar, mica and hornblende. It is formed by partial melting of the lower crust during its deformation over a billion years ago. The Precambrian Vishnu Schist and Zoroaster Granite are considered to be the basement structures or foundation upon which the overlying strata of the Grand Canyon are built.