Other

Boracite Group

Botryoidal Chalcedony

Hardness: 6.5-7

Botryoidal Hematite

Hardness: 5.5-6.5

Bottinoite Group

Bournonite Group

Brachiopod

Hardness: Variable

Brachiopod Fossil

Hardness: 3-5

Brackebuschite Supergroup

Brass

Hardness: 3-4

Braunite Group

Brick

Hardness: 3.0 - 5.5

Bronze

Hardness: 3-4

Brucite Group

Bukovite Group

Burbankite Group

Byströmite Group

Calcioferrite Group

Calcite

Hardness: 3

Calcite Group

Calomel Group

Calsilica

Hardness: 3 - 4

Canasite Group

Carminite Group

Carnelian

Hardness: 6.5 to 7

Carnotite Group

Carpholite Group

Celestite

Hardness: 3 - 3.5

Cerchiaraite Group

Cerite Supergroup

Cervantite Group

Chabournéite Group

Chalcanthite Group

Chalcedony

Hardness: 6.5 to 7

Chalcoalumite Group

Chalcocite-digenite Group

Chalcophanite Group

Chalcopyrite Group

Chalcostibite Group

Charoite in Tinaksite

Chevkinite Group

Chlorite

Hardness: 2-3

Chlorite Schist

Hardness: 2 to 3

Chrome Diopside

Hardness: 5.5 to 6.5

Gem

Chrysoberyl

Hardness: 8.5

Chrysocolla

Hardness: 2.5 to 3.5

Chrysocolla in Quartz

Gem

Chrysoprase

Hardness: 6.5 to 7

Chukhrovite Group

Cinnabrite

Hardness: 5.5 - 6

Citrine

Hardness: 7

Claudetite Group

Clay

Hardness: 1-2.5

Cobaltite Group

Columbite Group

Conch Shell

Hardness: 3.5

Confusionite

Copiapite Group

Copper Group

Coprolite

Hardness: 2-4

Coquimbite Group