Biotite (Black Mica)
Biotite (K(Mg,Fe++)3AlSi3O10(OH,F)2)
mineral
Category
Mineral, Often Found As A Rock
Browse mineral, often found as a rock specimens identified by the Rock Identifier community.
Olivine in Basalt matrix
Peridotite (Mg, Fe)2SiO4
igneous
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Carnelian Agate (with Quartz/Chalcedony)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
mineral
Ferruginous Sandstone
Arenite with Iron-Oxide Cement (FeO(OH)·nH2O / Fe2O3)
sedimentary
Sandstone (Ferruginous)
Clastic Sedimentary Rock (Litharenite)
sedimentary
Agate (specifically Botswana or Lake Superior style chalcedony)
Silicon Dioxide (SiO2)
mineral
Concretion with Quartz Veining
Septarian Concretion (CaCO3 / SiO2)
sedimentary
Chert (Iron-stained)
Chert (primarily Microcrystalline Quartz, SiO2)
sedimentary
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic Volcanic Rock)
igneous
Sandstone
Arenite (primarily SiO2)
sedimentary
Quartz Druze on Matrix
Silicon Dioxide (SiO2)
mineral
Gneiss
Gneiss
metamorphic
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite (SiO2 primarily)
sedimentary
Sandstone
Arenite (predominantly Quartz Sandstone)
sedimentary
Quartz Crystal (specifically a Double-Terminated variety)
Silicon Dioxide (SiO2) - Low Quartz
mineral
Greenstone / Diorite
Intermediate plutonic igneous rock
igneous
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Sandstone
Arenite (primarily Quartz, SiO2)
sedimentary
Diorite
Phaneritic intermediate plutonic rock
igneous
Unakite
Epidotized Granite
metamorphic
Amethyst
Amethyst (SiO2 with iron impurities)
mineral
Copper Ore with Chrysocolla and Azurite
Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O (Chrysocolla) / Cu3(CO3)2(OH)2 (Azurite)
mineral
Limonite (Iron Ore)
FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide)
mineral
Yellow Ochre / Limonite
Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)
mineral
Shale
Shale (Consolidated fine-grained clay/silt)
sedimentary
Sandstone (likely Iron-rich or Arkosic)
Arenite (SiO2 with FeO(OH) or Fe2O3 staining)
sedimentary
River Siltstone / Mudstone Pebble
Siltstone (composed of mixed silicate and carbonate minerals)
sedimentary
Quartzite with Feldspar
Quartzite (mainly SiO2) with inclusions of Potassium Feldspar (KAlSi3O8)
metamorphic
Sandstone with Quartz Veins
Arenite (primarily SiO2 with Fe2O3 staining)
sedimentary
Picture Jasper
Silicon dioxide (SiO2)
sedimentary
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
sedimentary
Dendritic Agate (River Pebble)
Silicon Dioxide (SiO2) with Manganese or Iron oxide inclusions
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic silicate with secondary mineral inclusions)
Igneous
Sandstone (Ferruginous)
Arenite (complex silicate composition with iron oxides)
sedimentary
Red Jasper (possibly Chert/Argillite)
Jasper (SiO2) with iron oxide inclusions
sedimentary
Chrysocolla
Hydrated copper silicate (Cu,Al)2H2Si2O5(OH)4·nH2O
mineral
Unakite (or Epidotized Granite)
Epidotized Granite (Composition: KAlSi3O8, Ca2(Al,Fe)3(SiO4)3(OH), SiO2)
metamorphic
Epidote
Epidote (formula: Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
mineral