Garnierite is a major Nickel (Ni) ore. Garnierite is a hydrous nickel silicate, with the serpentine group of minerals. It is an alteration of olivine, serpentine rocks, and can be associated with olivine, serpentine, chromite and talc. Garnierite is mined from laterite deposits, formed by weathering and secondary mineralization of igneous rocks. The nickel is contained in the blue-green bands of the ore in the photo. The specific gravity of this mineral ranges from 2.3 to 2.8 Nickel is ferro-magnetic, which, when used with iron and cobalt, manufactures a good strength magnet. Celestial visitors to the planet have a 5 to 20% mixture of Nickel-Iron, which distinguish them from earth rocks. Nickel is primarily used as an alloy to metals, with stainless steel being the major use of nickel. Other nickel alloys include super alloys, which are stronger and more corrosion resistant metals that are used in high temperature applications, where a particular strength is required.   Some information provided by USGS