Abundant rock outcroppings include dolomite, granite, gneiss, and mica schist. Metamorphic schist and gneiss are also found. It is found in metamorphic limestone, slate, mica schist, gneiss and granite. Corundum occurs as a mineral in mica schist, gneiss, and some marbles in metamorphic terranes. They primarily consist of metamorphic gneiss, granite, and schist. They consist primarily of metamorphic gneiss, granite, and schist. It is a common constituent of schist, gneiss, quartzite and other metamorphic rocks. More mafic rock such as hornblende-biotite gneiss and gabbro are occasionally found. There are various igneous intrusions including pegmatite, as well as bands of gneiss and schist. The bedrock is mostly biotite gneiss. It also occurs in metamorphic rocks such as gneiss and schists and skarns. Roofs are traditionally constructed from Alpine rocks such as pieces of schist, gneiss or slate. Gold occurs in quartz veins traversing in BIF, metavolcanics, and hornblende and biotite gneiss. This raised the Precambrian gneiss and schist that makes up the canyon walls. It is called nepheline syenite gneiss or litchfieldite.