Pentlandite

Nickel is a silvery metallic element. Most of the nickel mined comes from two types of deposits-laterites, in which the principal minerals are garnierite (hydrous nickel silicate) and nickeliferous limonite (hydrated iron oxide) and magmatic sulfide deposits, in which the principal mineral is pentlandite (iron nickel sulfide). The United States imports nearly all its primary nickel mainly from Australia, Canada, Norway, and Russia. Important uses are in alloy and stainless alloy steels, aluminum alloys, chemicals, copper alloys, electroplating, and superalloys for jet engines and industrial gas turbine components.

Source: http://resourcescommittee.house.gov/subcommittees/emr/usgsweb/materials/nickel.html ; original upload English Wikipedia, 4 August 2004 by Chris 73

This image is a work of the "Minerals in Your World" project, a cooperative effort between the United States Geological Survey and the Mineral Information Institute. The images were featured in the "Minerals and Materials Photo Gallery" on the website of the U.S House Subcommittee on Energy and Natural Resources. As a work of the U.S. federal government, the image is in the public domain in the United States.