- Calamine (Hemimorphite)
- Calaverite
- Calcite
- Caledonite
- Carnotite
- Cassiterite
- Celestine
- Celestite (Celestite)
- Celsian (Feldspar)
- Cerussite
- Chabazite
- Chalcanthite
- Chalcedony
- Chalcocite
- Chalcopyrite
- Chessylite (Azurite)
- Childrenite
- Chloanthite
- Chloragyrite
- Chlorite
- Chlorapatite
- Chondrodite
- Chromite
- Chrysoberyl
- Chrysocolla
- Chrysoprase (Chalcedony)
- Chrysotile (Serpentine)
- Cinnabar
- Citrine (Quartz)
- Clinoclase
- Clinozoisite
- Cobaltite
- Coesite
- Colemanite
- Columbite
- Conichalcite
- Copper
- Cordierite
- Cornetite
- Corundum
- Covellite
- Cristobalite
- Crocoite
- Cryolite
- Cubanite
- Cuprite
- Cyanotrichite