| CACOXENITE (Hydrated Iron Aluminum Phosphate Oxide Hydroxide) | |
| CALAVERITE (Gold Telluride) | |
| CALCIOVOLBORTHITE (Calcium Copper Vanadate Hydroxide) | |
| CALCITE (Calcium Carbonate) | |
| CALEDONITE (Copper Lead Carbonate Sulfate Hydroxide) | |
| 0 | CALOMEL (Mercury Chloride) |
| CANCRINITE (Sodium Calcium Aluminum Silicate Carbonate) | |
| 0 | CARBOCERNAITE (Calcium Sodium Strontium Cerium Barium Carbonate) |
| * | CARBONATES (Class) |
| CARLETONITE (Hydrated Potassium Sodium Calcium Carbonate Silicate Fluoride Hydroxide) | |
| CARNALLITE (Hydrated Potasium Magnesium Chloride) | |
| 0 | CARNELIAN (variety of Quartz - Silicon Oxide) |
| CARNOTITE (Hydrated Potassium Uranyl Vanadate) | |
| CASSITERITE (Tin Oxide) | |
| CATAPLEIITE (Hydrated Sodium Zirconium Silicate) | |
| CAVANSITE (Hydrated Calcium Vanadium Silicate) | |
| CELESTITE (Strontium Sulfate) | |
| CERUSSITE (Lead Carbonate) | |
| CHABAZITE (Hydrated Calcium Aluminum Silicate) | |
| CHALCANTHITE (Hydrated Copper Sulfate) | |
| 0 | CHALCEDONY (variety of Quartz - Silicon Oxide) |
| CHALCOCITE (Copper Sulfide) | |
| CHALCOPHYLLITE (Hydrated Copper Aluminum Sulphate Arsenate Hydroxide) | |
| CHALCOPYRITE (Copper Iron Sulfide) | |
| 0 | CHALCOSIDERITE (Hydrated Copper Iron Phosphate Hydroxide) |
| 0 | CHALCOTRICHITE (variety of Cuprite, Copper Oxide) |
| 0 | CHALK (a sedimentary rock) |
| CHAROITE (Hydrated Sodium Calcium Barium Strontium Silicate Hydroxide Fluoride) | |
| 0 | CHENGDEITE (Iridium Iron) |
| CHILDRENITE (Hydrated Iron Manganese Aluminum Phosphate Hydroxide) | |
| CHKALOVITE (Sodium Beryllium Silicate) | |
| 0 | CHLORAPATITE (the chlorine rich apatite) |
| CHLORARGYRITE (Silver Chloride) | |
| CHLORITE (Iron Magnesium Aluminum Silicate Hydroxide) | |
| CHONDRODITE (Magnesium Iron Silicate Fluoride Hydroxide) | |
| CHROMITE (Magnesium Iron Chromium Oxide) | |
| 0 | CHROMIUM (Cr) |
| CHRYSOBERYL (Berylium Aluminum Oxide) | |
| CHRYSOCOLLA (Hydrated Copper Silicate) | |
| 0 | CHRYSOPRASE (variety of Quartz - Silicon Oxide) |
| 0 | CHRYSOTILE (variety of Serpentine, Magnesium Iron Silicate Hydroxide) |
| CHURCHITE (Hydrated Yttrium Erbium Phosphate) | |
| CINNABAR (Mercury Sulfide) | |
| CITRINE (variety of Quartz- Silicon Oxide) | |
| CLAUSTHALITE (Lead Selenide) | |
| * | CLAYS (Group) |
| 0 | CLEAVELANDITE (variety of Albite, Sodium Aluminum Silicate) |
| 0 | CLIFFORDITE (Uranium Tellurate) |
| CLINOCHLORE (Magnesium Aluminum Silicate Hydroxide) | |
| CLINOCLASE (Copper Arsenate Hydroxide) | |
| CLINOHEDRITE (Hydrated Calcium Zinc Silicate) | |
| CLINOHUMITE (Magnesium Iron Silicate Fluoride Hydroxide) | |
| CLINOPTILOLITE (Hydrated Sodium Potassium Calcium Aluminum Silicate) | |
| 0 | COAL (an organic sedimentary rock) |
| 0 | COBALT (Co) |
| * | COBALTITE (Group) |
| COBALTITE (Cobalt Arsenic Sulfide) | |
| 0 | COBALTOCALCITE (alternate name for Sphaerocobaltite) |
| COCONINOITE (Hydrated Iron Aluminum Uranyl Phosphate Sulfate Hydroxide) | |
| 0 | COESITE (Silicon Dioxide) |
| COLEMANITE (Hydrated Calcium Borate Hydroxide) | |
| COLLINSITE (Hydrated Calcium Magnesium Iron Phosphate) | |
| COLUMBITE (Iron Magnesium Manganese Niobium Tantalum Oxide) | |
| 0 | COMETS (primordial icy rocks in space) |
| CONICHALCITE (Calcium Copper Arsenate Hydroxide) | |
| CONNELLITE (Hydrated Copper Sulfate Chloride Hydroxide) | |
| COPIAPITE (Hydrated Iron Magnesium Sulfate Hydroxide) | |
| COPPER (Cu) | |
| CORDIERITE (Magnesium Aluminum Silicate) | |
| 0 | CORDYLITE (Barium Cerium Lanthanum Carbonate Fluoride) |
| CORNETITE (Copper Phosphate Hydroxide) | |
| 0 | |
| CORUNDUM (Aluminum Oxide) | |
| COVELLITE (Copper Sulfide) | |
| CREEDITE (Hydrated Calcium Aluminum Sulfate Fluoride Hydroxide) | |
| CRISTOBALITE (Silicon Dioxide) | |
| CROCOITE (Lead Chromate) | |
| 0 | CROCIDOLITE (asbestiform variety of Riebeckite, Sodium Iron Magnesium Silicate Hydroxide) |
| CRYOLITE (Sodium Aluminum Fluoride) | |
| CUBANITE (Copper Iron Sulfide) | |
| 0 | CUMENGITE (Lead Copper Chloride Hydroxide) |
| CUMMINGTONITE (Magnesium Iron Silicate Hydroxide) | |
| CUPRITE (Copper Oxide) | |
| CUPROADAMITE (Copper Zinc Arsenate Hydroxide) | |
| CUPROSKLODOWSKITE (Hydrated Copper Uranyl Silicate) | |
| CYANOTRICHITE (Hydrated Copper Aluminum Sulfate Hydroxide) | |
| CYLINDRITE (Iron Lead Tin Antimony Sulfide) |