Quality Assessment and Grading ofDimension Stone in Krishnagiri District, Tamil Nadu, India

Abstract

Dimension stone are widely used for monuments, decorative stone, countertops and flooring. Group of crystalline rocks including igneous and metamorphic rocks are used as dimension stone and they are commercially referred as granites.In India, the state of Tamil Nadu, two third of area is covered by igneous and metamorphic terrain, which are widely used for production of commercial granites.The commercial granites made significant contribution to national economic growth. The Krishnagiri district is one of the districts in the state of Tamil Nadu, producing significant volume of dimension stone block, fordomestic usage as well as exporting to foreign countries. In the present study, an assessment has been made to investigate the quality of different type of commercial granites in this region. The dimension stones were assessed through investigation of desired geological quality and associated defects. There are 16 locations identified and rock samples were collected for such quality assessment. The desired qualities were assessed through close megoscopic observations. Rock samples collected from the quarrieswere cut down and thin sections were prepared. Petrological studies were carried out under petrological microscope for identification of minerals and optical properties. Based on the desired quality and associated defects, the granites were graded into four categories as A,B,C &D. The grade A refers to top grade dimension stone with high market value and grade D ranked in the lowest category.