An ore is a valuable mineral deposit that has sufficient utility to be mined profitably. Gangue is mineral particles found within an ore deposit that are valueless and must be discarded. An example of gangue within an ore is fluorite found within lead-zinc deposits.

Other common examples of gangue are:

• Quartz
• Calcite
• Magnesite
• Gypsum
• Pyrite

Figure: As seen, ore grade material is almost always surrounded by uneconomic gangue material.