Chwilio am Fwynau (Saesneg yn unig)
- Cacoxenite
- Calaverite
- Calciovolborthite
- Calcite
- Caledonite
- Carbonate-cyanotrichite
- Carbonate-fluorapatite
- Carbonate-hydroxylapatite
- Caryopilite
- Cassiterite
- Celadonite
- Celestine
- Celsian
- Cerussite
- Cesarolite
- Chalcanthite
- Chalcoalumite
- Chalcocite
- Chalconatronite
- Chalcophanite
- Chalcophyllite
- Chalcopyrite
- Chamosite
- Chenite
- Chlorite
- Chloritoid
- Chromite
- Chrysocolla
- Chrysotile
- Cinnabar
- Clinochlore
- Clinoclase
- Clinotyrolite
- Clinozoisite
- Clintonite
- Cobalt pentlandite
- Cobaltite
- Collophane
- Coloradoite
- Conichalcite
- Connellite
- Cookeite
- Copiapite
- Copper
- Coquimbite
- Cordierite
- Corkite
- Coronadite
- Corrensite
- Corundum
- Cosalite
- Cotunnite
- Covellite
- Crandallite
- Crossite
- Cryptomelane
- Cubanite
- Cumengéite
- Cuprite
- Cymrite