The Precambrian complex in the Serbo-Macedonian Massif is made up of gneiss, mica schist and gabbro amphibolite with small masses of marble and metarhyolite. Gneiss is connected to the lower part of the massif and includes minerals such as muscovite, biotite and augen. Mica schist tends to occur in thin bands while gabbro amphibolites represent the metamorphosed magma intrusions and basic rocks with meta-tuff sometimes interspersed with gneiss and mica schist in bands and lenses.