Copper ores are typically found in which group of minerals?

• A. Chalcopyrite, pyrite, sphalerite
• B. Bornite, chalcocite, enargite
• C. Graphite, pyrite, marcasite
• D. Zircon, apatite, fluorite

Answer: (B)

Copper ore minerals are mainly copper-bearing sulfide minerals. Bornite, chalcocite, and enargite are classic examples of copper minerals mined as ore: bornite is a copper iron sulfide, chalcocite is copper sulfide, and enargite is a copper arsenic sulfide. These form the ore deposits we extract for copper.

The other groups mix non-copper minerals (like pyrite and sphalerite, or graphite and marcasite, or zircon, apatite, and fluorite), so they don’t represent copper ores as a set. Chalcopyrite is a well-known copper ore, but the list with only copper-containing minerals—bornite, chalcocite, and enargite—best fits the idea of copper ores.