The sandstone is derived from metamorphic and volcanic fragments.
en.wikipedia.org The most abundant rock types are quartzite and banded iron formation, with subordinate metamorphic gneisses, metaconglomerates and pelitic to semi-pelitic quartz-muscovite schists.
en.wikipedia.org For example, many metamorphic limestones, marbles, and calc-schists, with crystalline dolomites, contain silicate minerals such as mica, tremolite, diopside, scapolite, quartz and feldspar.
en.wikipedia.org Their geological formation is metamorphic gneiss, veined with felspar and quartz, and interspersed with reddish porphyrite.
en.wikipedia.org The southern three quarters of the region consists of metamorphic rock such as gneiss, schist, mica, and migmatite.
en.wikipedia.org