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
Arizona Mining and Mineral Museum Parts of the collection were expected to be included in the planned centennial museum, which was to be called the Arizona Experience Museum. The mineral collection features displays of minerals from well-known Arizona mineral localities and specimens from Arizona copper mines, including a piece of native copper that is in its longest dimension. Displays on the lapidary arts feature faceted gemstones and cabochons made from Arizona minerals. Mineralogical principles are illustrated by displays on mineral crystal systems, crystal habits, fluorescent minerals, and causes of color. Unusual items in the mineral collection include a piece of the Meteor Crater meteorite, fulgurites,