Banded Gneiss (River Rock/Pebble)
Gneiss (specifically a banded variety often found as a river rock)
Metamorphic Rock
Category
Sedimentary Rock (Specifically A Concretion Or Possibly A Geode)
Browse sedimentary rock (specifically a concretion or possibly a geode) specimens identified by the Rock Identifier community.
Amethyst
Silicon Dioxide (SiO2) with iron impurities
mineral
Blue Lace Agate (with Amethyst Geode center)
Silicon Dioxide (SiO2) - Cryptocrystalline Chalcedony
mineral
Golem
Megaton Pokémon (Lithos sapiens megalithos)
igneous/sedimentary (Rock/Ground type)
Quartz
Quartz (SiO₂)
Mineral
Pink Granite (River Pebble)
Felsic Intrusive Igneous Rock
igneous
Crushed Limestone
Calcite-rich Sedimentary Rock (CaCO3)
sedimentary
Fire Opal (Common/Precious in Matrix)
Hydrated Silica (SiO2·nH2O)
mineral
Sandstone (likely Fossilized Wood or Concrete Simulacrum)
Arenite / Silicified Wood / Anthropogenic Concrete
sedimentary
Blue Chalcedony
Silicon Dioxide (SiO2) - Microcrystalline Quartz
mineral
Limestone
Calcareous Sedimentary Rock (CaCO3)
sedimentary
Fossiliferous Limestone (Coquina)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Limestone
Calcareous sedimentary rock (primarily CaCO3)
sedimentary
Thunderegg (Agate-filled Geode Node)
Silicon dioxide (SiO2) with various inclusions
sedimentary/igneous association
Granodiorite
Granodiorite (Intermediate to Felsic Intrusive Rock)
igneous
Quartz Geode (Nodule)
Silicon Dioxide (SiO2)
sedimentary or igneous
Granitic Sand
Detrital sediment (predominantly Quartz, Feldspar, and Mica)
sedimentary
Ironstone (likely Ferruginous Siltstone/Sandstone)
Ferruginous sedimentary rock (FeOx-rich clastic)
sedimentary
Gneiss
Gneiss
metamorphic
Chert (specifically Banded Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Amethyst
Silicon Dioxide (SiO2) with Iron impurities
mineral
Amethyst
Amethyst (Silicon Dioxide, SiO2)
mineral
Basalt with Epidote Veining
Basalt (Mafic Extrusive Rock) with Ca2(Al,Fe)3(SiO4)3(OH)
igneous
Moqui Marble (Concretion)
Iron Oxide Concretion (Hematite-cemented Sandstone)
sedimentary
Amethyst
SiO2 (Silicon Dioxide with iron impurities)
mineral
Howlite and Purple Amethyst Druzy
Calcium Borosilicate Hydroxide (Howlite) and Silicon Dioxide (Quartz/Amethyst)
mineral
Amethyst (Tumbled)
Quartz (Silicon Dioxide, SiO2) with iron impurities
mineral
Moqui Marble (Concretion)
Iron oxide concretion (Goethite/Hematite and Sandstone)
sedimentary
Rhodonite
Manganese Silicate (Mn,Fe,Mg,Ca)SiO3
mineral
Red Jasper (possibly Brecciated)
Jasper (Silicon Dioxide, SiO2)
sedimentary
Gneiss
Gneiss (High-grade regional metamorphic rock)
metamorphic
Carnelian Agate
Chalcedony (SiO2) with iron oxide inclusions
mineral
Amethyst
Amethyst (Silicon Dioxide - SiO2 with iron impurities)
mineral
Chert or Flint (polished/water-worn)
Chert (a microcrystalline or cryptocrystalline variety of quartz, SiO2). Flint is a specific variety of chert.
Sedimentary (most likely, as Chert is a sedimentary rock often found as nodules in limestone or as bedded deposits; however, it can also form by metasomatic replacement, which leans towards metamorphic processes under certain conditions)
Celestite (Celestine)
Strontium sulfate (SrSO4)
Mineral
Amethyst Quartz
Silicon Dioxide (SiO2) with iron impurities
mineral
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Jasper (specifically a banded or dark variety)
Silicon Dioxide (SiO2) with impurities
sedimentary
Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
mineral
Banded Calcite (often sold as Caribbean Calcite or Pink Calcite)
Calcium Carbonate (CaCO3)
mineral
Shungite
Shungite (carbon-rich Precambrian mineraloid)
mineral
Green Kyanite
Kyanite (Al2SiO5)
mineral