Based on physical characteristics, industrial diamonds are classified into three types, viz. Carbondo, Bort and Ballas. They are discussed below:
1. Carbondo: There are hard, tough, black diamonds, and are utilized for dies in wire drawing, for diamond drill-bits used in exploring for ores and oil, and for tools employed in dressing. Diamond-tipped tools are used for boring metals and hard substances, such as Bakelite, in the automobile and electrical industries where precision work in necessary.
2. Bort: Black or yellow coloured bort presents imperfect crystal forms. In the industrial field, it often replaces carbonados for many industrial purposes because of its lower cost. It is extensively employed in the precision manufacture of aero plane and motor-car engines, both for boring and for abrasion of surfaces. Diamond rock-drill bits are now mechanically set with small borts, which make them cheaper than carbon bits and thus greatly lowers the cost of diamond drilling. Borts are often employed for drilling b lasting holes.
Diamond dust made by grinding bort is used as an abrasive for the cutting of gemstones, minerals and carbides. Crushed diamonds are now impregnated in a molten metal bond for fast-cutting wheels.
3. Ballas: There are round–shaped, very hard, imperfectly crystallized diamonds which often look like quartz. There are also used for various industrial activities.