Ore
Definition
A naturally occurring mineral or rock from which a metal or valuable mineral can be profitably extracted.
Example
Galena is an ore of lead, while chalcopyrite is an important ore of copper.
Economic Geology
An "ore" is not a strictly scientific term but an economic one. It refers to rock containing minerals with important elements—typically metals—that can be extracted from the earth at a profit. Whether a deposit is considered an ore depends on the concentration of the mineral and the market price of the metal. If the price drops, a mine might close because the rock is no longer "ore" but just waste rock.
Ore Minerals vs. Gangue
In mining, the valuable material is the <strong>ore mineral</strong> (e.g., Galena for lead, Chalcopyrite for copper). The worthless rock surrounding it is called <strong>gangue</strong> (e.g., quartz, calcite). The goal of metallurgy is to separate the ore from the gangue. Examples of famous ores include Bauxite (Aluminum), Hematite (Iron), and Cinnabar (Mercury).