Basalt
Aphanitic mafic volcanic rock (primarily plagioclase feldspar and pyroxene)
Category
Browse metamorphic (likely gneiss or schist based on texture) specimens identified by the Rock Identifier community.
Basalt
Aphanitic mafic volcanic rock (primarily plagioclase feldspar and pyroxene)
Sandstone (with potential trace fossils)
Clastic sedimentary rock (primarily SiO2)
Sandstone (likely Quartzite-grade)
Arenite (primarily SiO2)
River Stone (likely Mudstone or Siltstone)
Lutite (Clastic sedimentary rock composed of clay and silt-sized particles)
Basalt
Mafic Igneous Rock (primarily Plagioclase and Pyroxene)
Basalt
Basalt
Petrified Wood
Silicified Wood (SiO2)
Granite
Phaneritic Plutonic Felsic Rock (SiO2, KAlSi3O8, NaAlSi3O8, CaAl2Si2O8)
Limestone
Calcium Carbonate (CaCO3)
Greenschist
Greenschist (Major minerals include Chlorite, Actinolite, and Epidote)
River Rock (likely Quartzite or Chert)
Quartzite (primarily SiO2)
Muscovite Mica (Granitic Pegmatite)
Muscovite - KAl2(AlSi3O10)(OH)2
Pink Quartzite
Quartzite (SiO2 with iron oxide impurities)
Quartzite
Quartzite (primarily SiO2)
Quartzite
Quartzite (primarily SiO2)
Dendritic Agate
Silicon Dioxide with Manganese or Iron Oxide inclusions (SiO2 + Mn/Fe)
Pumice
Vesicular volcanic glass (primarily SiO2 with Al2O3)
Pebble (likely Quartzite or Chert)
Clastic Sediment, potentially composed of SiO₂ (Quartz)
Shatter Cone
Impactite (Shatter Cone texture)
Green Quartzite (Aventurine-like)
Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)
Quartzite Pebble (Beach Stone)
Quartzite (primarily SiO2)
Quartzite (River Cobble)
Quartzite (Metamorphosed Quartz Sandstone, SiO2)
Quartzite (Ferruginous)
Recrystallized Quartz (SiO2) with Iron Oxide inclusions
River Pebble (Quartzite/Siltstone mixture)
Silicon Dioxide (SiO2) mixture with varied clastic minerals
Chert (Field Stone/Jasper variety)
Microcrystalline Quartz (SiO2)
Chert (Iron-Stained)
Microcrystalline Silica (SiO2)
Granite
Granite (Mainly Quartz, Feldspar, and Mica)
Amazonite
KAlSi3O8 (Potassium Feldspar, variety of Microcline)
Marble
Recrystallized Calcite (CaCO3)
Sunstone with Black Tourmaline (Arfvedsonite)
Feldspar (Na,Ca)(Al,Si)4O8 with Schorl Na(Fe3+)3Al6(Si6O18)(BO3)3(OH)3(OH)
Sandstone
Arenite (primarily SiO2)
Vesicular Basalt with Quartz
Vesicular Basalt (SiO2 inclusions)
Andesite
Andesite (Intermediate Extrusive Volcanic Rock)
Granodiorite
Granodiorite (Intermediate intrusive igneous rock)
Basalt (with Porphyritic/Vesicular texture)
Extrusive mafic igneous rock
Coquina or Fossiliferous Limestone
Fossiliferous Calcarenite (CaCO3)
Basalt with Quartz/Calcite matrix
Basalt (SiO2 with Ca/Mg/Fe silicates) on a Mineral Matrix
Limonite/Goethite on Shale
Hydrous ferric oxides (FeO(OH)·nH2O) often associated with argillaceous rock
Marble (Fire and Ice or Pink Veined)
Metamorphosed Limestone (principally CaCO3)
Basalt with Porphyritic Texture
Porphyritic Basalt
Basalt
Basalt (Mafic volcanic rock)
Chert (Flint Nodules)
Chert (Cryptocrystalline variety of Quartz, SiO2)