The use of diamond tools has, over recent years, become widely accepted as the most economical method of processing natural stone. The ever-increasing pressure for higher production rates and better surface textures in finished stone products has resulted in diamond cutting becoming one of the major growth areas in the stone industry of Turkey. In this study, a general defect characterization in the continuous disc type diamond cutting tools used in marble, granite, and natural stone cutting has been investigated. Transverse rupture tests were carried out with different matrix and diamond compositions. The toughness of the tested materials was determined. (C) 2001 Elsevier Science Inc. All rights reserved.