Chemical element chemical bonds, they form chemical compounds. Only a minority of elements are found uncombined as relatively pure minerals. Among the more common of such native elements are copper, silver, gold, carbon (as coal, graphite, or diamonds), and sulfur. All but a few of the most inert elements, such as noble gases and noble metals, are usually found on Earth in chemically combined form, as chemical compounds. While about 32 of the chemical elements occur on Earth in native uncombined forms, most of these occur as mixtures. For example, atmospheric air is primarily a mixture of nitrogen, oxygen, and argon, and
Zhejiang Huayou Cobalt buying cobalt mined by hand in DRC entirely. Zhejiang Huayou Cobalt Huayou Cobalt Co., Ltd is primarily a supplier of cobalt, including cobalt tetroxide, cobalt oxide, cobalt carbonate, cobalt hydroxide, cobalt oxalate, cobalt sulfate, and cobalt monoxide. It is headquartered in the Tongxiang Economic Development Zone of Zhejiang, China. A subsidiary, Congo DongFang International Mining, has been involved in several controversies around sourcing of cobalt in the Democratic Republic of the Congo. According to a joint Amnesty International and African Resources Watch report, Congo DongFang International Mining, a subsidiary of Huayou Cobalt, sources cobalt from primitive "artisanal" mines in the