Occurrence chromium is obtained from the chromite (FeCr2O4). Chromium is obtained commercially by heating the chromite in the presence of aluminum or silicon (through a process of reduction). About half of the South African chromite ore is extracted. Also obtained in large quantities in Kazakhstan, India and Turkey untapped deposits are abundant, but are geographically concentrated in Kazakhstan and southern Africa. In 2000 there were approximately fifteen million tons of chromite, of which most is used for alloys (about 70 ), eg for ferrochrome (an alloy of chromium and iron with some carbon). Another part (about 15 ) is directly used as refractory material, the rest in the chemical industry for various chromium compounds.Deposits have been discovered chromium metal, though scanty, in a Russian mine (Udachnaya) occur in the metal samples, where the reducing environment has facilitated the production of elemental chromium and diamond. 19 radioisotopes have been characterized, the most stable chromium-50 with a half-life of over 1.8 1017 years, followed by chromium-51 with one of 27.7025 days. The rest have half-lives of less than 24 hours, most less than a minute. This element also has two meta states. Chromium-53 is the decay product of manganese-53. Chromium isotope content are related to manganese, which is used in geology. The isotope ratios of Mn-Cr evidence reinforce the aluminum-26 and palladium-107 in the early solar system.Variations in cromo-53/cromo-52 relations and Mn / Cr in some meteorites indicate an initial 53Mn/55Mn suggesting that isotope ratios are Mn-Cr in situ decay of 53mn in differentiated planetary bodies. Therefore, the 53Cr gives further evidence nucleosint ticos processes just before the coalescence of the solar system. The atomic weight of isotopes of chromium range from 43 amu (chromium-43) to 67 amu (chromium-67). The first decay mode before the most abundant stable isotope, chromium-52, is electron capture, while after this, is the beta decay