Diamond is best known for its gem qualities, but some of its unique properties make it ideal for many industrial and research applications as well.  Current information on gem-grade diamond can be found in the U.S. Geological Survey (USGS) Minerals Yearbook chapter on gemstones.  Diamond is the hardest known material and has the highest thermal conductivity of any material at room temperature. Diamond is more than twice as hard as cubic boron nitride or silicon nitride, which are the nearest competitors.  Because it is the hardest substance known, diamond has been used for centuries as an abrasive in grinding, drilling, cutting, and polishing, and industrial-grade diamond continues to be used as an abrasive for many applications.  Diamond that does not meet gem-quality standards for clarity, color, shape, or size is used as industrial-grade diamond.  Even though it has higher unit cost, diamond has proven to be more cost-effective in many industrial processes because it cuts faster and lasts longer than its rival abrasive materials.  Diamond also has chemical, electrical, optical, and thermal characteristics that make it the best material available to industry for wear- and corrosion-resistant coatings, special lenses, heat sinks in electrical circuits, wire drawing, and advanced technologies. Both synthetic and natural diamonds have industrial uses, but synthetic industrial diamond is superior to its natural diamond counterpart because it can be produced in large quantities.  In many cases, its properties can be tailored to specific applications.  It is for these reasons that manufactured diamond accounts for more than 90% of the industrial diamond used in the United States and the world, and if you just read all of that you deserve 10% off your first purchase - just mention we tried to bore you to  death and receive 10% off your first time order of diamond blades or wire.