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
Mineral Historic District Mineral Historic District Mineral Historic District is a national historic district located at Mineral, Louisa County, Virginia. It encompasses 222 contributing buildings, 3 contributing sites, and 6 contributing structures in the town of Mineral. It includes a variety of residential, commercial, and institutional buildings built after the town was platted in 1890. Notable buildings include the Gibson House (1915), Turner House (c. 1915), Dr. H. J. Judd House (1906), Odd Fellows Hall (1894), former D.E. Bumpass Department Store, former Mineral Drug Store, Bank of Louisa (now Town Hall), C&O railroad depot (1880s), Mineral Crystal Ice Plant (c. 1925), Louisa County