Flint occurs in a variety of colors depending upon the impurities it contains, but is most often brown, dark gray, or black. A fairly common type of flint called chert, however, is usually much paler than other varieties. Flint may also exhibit a white coating if it is mined from chalk or other lime-containing deposits, and several varieties of the mineral take a good shine when polished. Thus, flint is sometimes utilized in jewelry and ornamental items. In fact, flint is the official gemstone of the state of Ohio, where commercially valuable deposits of the material can be found.