Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.[1] [2] Ore is extracted from the earth through mining and treated or refined, often via smelting, to extract the valuable metals or minerals.[3] The grade of ore refers to the concentration of the desired material it contains. The value of the metals or minerals a rock contains must be weighed against the cost of extraction to determine whether it is of sufficiently high grade to be worth mining, and is therefore considered an ore.[3]

Iron ore (banded iron formation)
Iron ore (Banded iron formation, Minnesota) consisting of magnetite as main ore mineral (silver-grey bands) and quartz as main gangue mineral (light and red bands). The red bands contain also hematite; most of it, otherwise a valuable iron ore mineral, cannot be recovered economically because it is finely intergrown with quartz
Manganese ore psilomelane (size: 6.7 × 5.8 × 5.1 cm)
Lead ore galena and anglesite (size: 4.8 × 4.0 × 3.0 cm)
Gold ore (size: 7.5 × 6.1 × 4.1 cm)
Minecart on display at the Historic Archive and Museum of Mining in Pachuca, Mexico

Minerals of interest are generally oxides, sulfides, silicates, or native metals such as copper or gold. Ores must be processed to extract the elements of interest from the waste rock. Ore bodies are formed by a variety of geological processes generally referred to as ore genesis.