Synthetic diamond "nanocrystalline" and "microcrystalline" diamond, respectively. Synthetic diamond is the hardest known material, where hardness is defined as resistance to indentation. The hardness of synthetic diamond depends on its purity, crystalline perfection and orientation: hardness is higher for flawless, pure crystals oriented to the <nowiki>[</nowiki>111<nowiki>]</nowiki> direction (along the longest diagonal of the cubic diamond lattice). Nanocrystalline diamond produced through CVD diamond growth can have a hardness ranging from 30% to 75% of that of single crystal diamond, and the hardness can be controlled for specific applications. Some synthetic single-crystal diamonds and HPHT nanocrystalline diamonds (see hyperdiamond) are harder than any known
National Mineral Development Corporation National Mineral Development Corporation </nowiki> NMDC Limited, previously known as National Mineral Development Corporation, is an Indian state-controlled mineral producer. It is 72.43% owned by the Government of India, under the administrative control of the Ministry of Steel. It is involved in the exploration of iron ore, copper, rock phosphate, limestone, dolomite, gypsum, bentonite, magnesite, diamond, tin, tungsten, graphite etc. It is India's largest iron ore producer and exporter producing more than 35 million tons of iron ore from 3 fully mechanized mines in Chhattisgarh and Karnataka. It also operates the only mechanized diamond mine in the country at Panna