Granite is a coarse grained plutonic igneous rock. It consist essentially of minerals such as quartz, feldspar and mica. During the recent years the use of granites as monumental and decorative stones has increased world-wide. It is exported to various countries, particularly to Italy, Japan and Korea. In India, granite deposits are mainly distributed in Orissa, Andhra Pradesh , Karnataka and Tamilnadu. Particularly in Tamilnadu granites are distributed in Salem, Dharmapuri, Coimbatore, Vellore, Tiruvannamalai and Madurai districts.

Igneous Rocks

      Igneous rocks are formed by the solidification of magma either underneath the surface or above it . On the basis of the depth of their formation they may be classified into plutonic rocks, hypabyssal rocks and volcanic rocks.

   It is a dark grey, fine grained granular rock comprised of dark glistening grains of pyroxenes and pale yellow feldspars .

Gabbro

    It is a medium grained, equigranular, greyish dark glistening grains of pyroxenes and pale grey labrodorite. It was collected from Nellore.