Minerals

O'danielite

Hardness: 4

Oberthürite

Obradovicite-kcu

Hardness: 2.5

Obradovicite-nacu

Hardness: 2

Obradovicite-nana

Hardness: 2

Odigitriaite

Hardness: 5

Odikhinchaite

Odinite

Hardness: 2.5

Odintsovite

Hardness: 5 - 5.5

Oenite

Hardness: 5 - 5.5

Offretite

Hardness: 4 - 4.5

Oftedalite

Hardness: 6

Ogdensburgite

Hardness: 2

Ognitite

Ohmilite

Hardness: 3.5

Ojuelaite

Hardness: 3

Okanoganite-(y)

Hardness: 4

Okayamalite

Hardness: 5.5

Okenite

Hardness: 4.5 - 5

Okhotskite

Okieite

Okruschite

Oldhamite

Hardness: 4

Olekminskite

Hardness: 3

Olenite

Hardness: 7

Olgite

Hardness: 4.5

Olivine

Olkhonskite

Hardness: 8

Olmiite

Hardness: 5 - 5.5

Olmsteadite

Hardness: 4

Olsacherite

Hardness: 3 - 3.5

Olshanskyite

Hardness: 3.5 - 4

Olympite

Hardness: 4

Omariniite

Omeiite

Hardness: 7

Ominelite

Hardness: 7

Omongwaite

Omphacite

Hardness: 5 - 6

Omsite

Hardness: 3

Ondrušite

Hardness: 2 - 3

Oneillite

Hardness: 5 - 6

Onoratoite

Oosterboschite

Hardness: 5

Gem

Opal

Hardness: 5.5 - 6.5

Ophirite

Hardness: 2

Oppenheimerite

Orcelite

Ordonezite

Hardness: 6.5

Oregonite

Hardness: 5

Oreillyite

Organovaite-mn

Hardness: 5

Organovaite-zn

Hardness: 5

Orickite

Hardness: 3.5

Orientite

Hardness: 4 - 5

Orileyite

Orlandiite

Orlite

Orlovite

Hardness: 2 - 3

Orlymanite

Hardness: 4 - 5

Orpiment

Hardness: 1.5 - 2

Orschallite

Hardness: 4

Orthobrannerite

Hardness: 5.5

Orthocuproplatinum

Hardness: 4

Orthojoaquinite-(ce)

Hardness: 5 - 5.5

Orthojoaquinite-(la)

Hardness: 5

Orthominasragrite

Hardness: 1

Orthopinakiolite

Hardness: 6

Orthoserpierite

Orthowalpurgite

Hardness: 4.5

Osakaite

Osarizawaite

Hardness: 3 - 4

Osarsite

Hardness: 6

Osbornite

Hardness: 8.5

Oscarkempffite

Hardness: 3 - 3.5

Osmium

Hardness: 6 - 7

Osumilite

Hardness: 5 - 6

Osumilite-(mg)

Hardness: 5 - 6

Oswaldpeetersite

Hardness: 2 - 3

Otavite

Hardness: 3.5 - 4

Otjisumeite

Hardness: 3

Ottemannite

Hardness: 2

Ottensite

Hardness: 3.5

Ottohahnite

Hardness: 2.5

Ottoite

Ottrelite

Hardness: 6 - 7

Otwayite

Hardness: 4

Oulankaite

Hardness: 3.5 - 4

Ourayite

Hardness: 2

Oursinite

Hardness: 3 - 3.5

Ovamboite

Overite

Hardness: 3.5 - 4

Owensite

Hardness: 3.5

Owyheeite

Hardness: 2.5

Oxammite

Hardness: 2.5

Oxo-magnesio-hastingsite

Hardness: 6

Oxo-mangani-leakeite

Oxy-chromium-dravite

Hardness: 7.5

Oxy-dravite

Oxy-foitite

Hardness: 7

Oxy-schorl

Hardness: 7

Oxy-vanadium-dravite

Hardness: 7

Oxybismutomicrolite

Oxycalciomicrolite

Oxycalciopyrochlore

Oxycalcioroméite

Oxykinoshitalite

Hardness: 2.5

Oxynatromicrolite

Oxyphlogopite

Hardness: 3

Oxyplumboroméite

Hardness: 5

Oxystannomicrolite

Oxystibiomicrolite

Oxyvanite

Hardness: 7 - 7.5

Oyelite

Hardness: 5

Oyonite

Hardness: 3 - 3.5

Ozerovaite