Abstract
Building stones can be divided into two groups: raw stone and stone product. In Korea, they consist of granite, diorite, gabbro, andesite, tuff, slate and marble, of which granite is main product. The disribution area is approximately $31,753km^2$. The enterprises of building stone are about 1,500 at present. The granites for building stone are biotite granite, hornblende granite. granodiorite and porphyritic granite, of different colors (white, pink, grey, green and black). The compressive strength of granite ranges from 813 to $1,338kg/cm^2$, hardness from 78 to 101 and water absorption ratio from 0.09 to 0.40%. The weight reduction ratio of granite for 14 hours in aqua regia+$KMnO_4$solution is 0.3~4.5wt.%. There are eighty granite quarries in Korea. Marbles can also be extensively used for building but only a few mines are operated at present.