Gangue minerals are minerals that are not considered ore at a given time, but may become ore in the future. They are typically silicates, carbonates, or fluorides, but can also be sulfides. Gangue minerals are found in ore deposits, where they are mixed with the ore as impurities in the form of stone, sand, or rock. During mining, gangue is usually extracted along with the ore, and then separated out using mineral processing. This process can be complicated and depends on the minerals involved.