A tool insert comprising a composite diamond abrasive compact and a method of its production are provided. The composite abrasive compact is characterized by an intermediate layer between the diamond compact and the cemented carbide support. The intermediate layer consists essentially of discrete cubic boron nitride particles constituting 60 to 40 percent by volume of the intermediate layer, carbide particles, preferably tungsten carbide particles and diamond solvent, preferably cobalt. The carbide particles and diamond solvent together constitute 40 to 60 percent by volume of the intermediate layer and the diamond solvent constitutes 15 to 25 percent by volume of the carbide/solvent combination.