Banded Agate (specifically Carnelian Agate)
Silicon dioxide (SiO2) - Chalcedony variety
mineral
Category
Rock
Browse rock specimens identified by the Rock Identifier community.
Sandstone (Quartzose)
Arenite (primarily SiO2)
sedimentary
Quartz (Smoky/Milky Pebble)
Silicon Dioxide (SiO2)
mineral
Apache Tear (Obsidian)
Hydrated volcanic glass (SiO2 with inclusions)
igneous
Muscovite Mica
Muscovite: KAl2(AlSi3O10)(OH)2
mineral
Quartz vein in Host Rock
Crystalline Silicon Dioxide (SiO2) in Lithic Matrix
metamorphic
Basalt
Basalt (Mafic Extrusive)
igneous
Sandstone (Quartz Arenite)
Sandstone (dominated by SiO2 quartz grains)
sedimentary
Basalt
Basalt (Mafic volcanic rock)
igneous
Sandstone (Beach Pebble)
Clastic sedimentary rock (primarily Quartz and Feldspar)
sedimentary
Sandstone (Gneissic or Banded)
Clastic Sedimentary Rock (composed predominantly of SiO2)
sedimentary
Epidote (or Epidote-rich rock)
Epidote. Mineral formula: Ca2(Al,Fe)3(SiO4)3(OH).
Mineral, often found in metamorphic rocks but also in sedimentary and igneous rocks
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
River Cobble (likely Sandstone or Siltstone type)
Sandstone or Siltstone (common rock types that form river cobbles)
Sedimentary Rock (specifically a clastic sedimentary rock formed into a cobble)
Sandstone (likely Quartz Sandstone)
Arenite (composed primarily of SiO2)
sedimentary
Basalt
Basalt (composition mainly of Plagioclase feldspar, Pyroxene, and Olivine)
igneous
Granite (Weathered)
Plutonic Igneous Rock (Granitic)
igneous
Basalt
Basalt (Mafic volcanic rock)
igneous
Serpentine
Serpentine-group ((Mg,Fe,Ni,Al,Zn,Mn)3(Si,Al,Fe)2O5(OH)4)
metamorphic
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Quartzite River Rock
Quartzite (Silicon Dioxide, SiO2)
metamorphic
Granite (Phaneritic Igneous Rock)
Granite
igneous
Sandstone
Arenite (SiO2 based with quartz, feldspar, or lithic fragments)
sedimentary
Snowflake Obsidian (or similar porphyritic volcanic rock)
Obsidian with Spherulites (if glassy), or Porphyritic Rhyolite/Andesite (if crystalline groundmass)
igneous
Quartz Vein / Milky Quartz
Silicon Dioxide (SiO2)
mineral
Drill Core Sample
Cylindrical Rock Core (Specific mineralogy varies by extraction site)
Metamorphic (Likely Gneiss or Schist based on texture)
Orthoclase Feldspar
Potassium Aluminum Silicate (KAlSi3O8)
mineral
Biotite Schist (likely)
Biotite Schist (rock), Biotite (mineral)
Metamorphic
Scoria (Basaltic)
Vesicular Basalt
igneous
Pumice
Pumiceous rhyolite
igneous
Granite Sand (Decomposed Granite)
Grus / Quartz-Feldspar Detritus
sedimentary
Kimberlite
Kimberlite
igneous
Peridotite (with Olivine)
Peridotite (rich in Olivine, (Mg,Fe)2SiO4)
igneous
Mica Schist
Crystalline Schist (often containing Muscovite, Biotite, and Quartz)
metamorphic
Yellow Quartzite
Quartzite (primarily SiO2)
metamorphic
Granite
Granite (Phaneritic Igneous Rock)
igneous
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Lava Rock with Fabric Impression
Scoria or Basalt with anthropogenic impressions
igneous
Granite Pebble (River Rock)
Granite (composed primarily of Quartz, Feldspar, and Mica)
igneous
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite (SiO2 based)
sedimentary
Grey Granite
Phaneritic Felsic Igneous Rock (primarily Quartz, Feldspar, and Mica)
igneous