Carnelian
Carnelian (Silicon Dioxide - SiO2)
Category
Browse sedimentary rock (specifically a concretion or possibly a geode) specimens identified by the Rock Identifier community.
Carnelian
Carnelian (Silicon Dioxide - SiO2)
Fire Opal (in matrix)
Hydrated Silica (SiO2·nH2O)
Rough Amethyst
Silicon Dioxide (SiO2) with Iron impurities
Agate
Silicon Dioxide (SiO2)
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Sandstone (with Iron Staining)
Clastic Sedimentary Rock (primarily SiO2 with Fe2O3 oxides)
Chalcedony (Agate/Chert)
Silicon Dioxide (SiO2)
Amethyst (Faceted)
Amethyst (Silicon Dioxide with iron impurities, SiO2)
Amethyst Quartz Druse
Silicon Dioxide (SiO2) with iron impurities
Chert (and Chert Geode)
Silicon Dioxide (SiO2)
Sardonyx Cameo
Silicon Dioxide (SiO2) - variety Cryptocrystalline Quartz
Smoky Quartz
Silicon Dioxide (SiO2)
Limestone
Calcium Carbonate (CaCO3)
Banded Agate / Lace Agate
Agate (Silica/Quartz) - SiO2
Banded Agate
Microcrystalline Quartz (SiO2) with impurities
Chert Nodule
Microcrystalline Quartz (SiO2)
Biotite Mica
K(Mg,Fe)3AlSi3O10(OH)2
Asphalt Concrete (Bituminous Conglomerate)
Anthropogenic Bituminous Conglomerate
Gneiss
Gneiss
Clear Quartz Crystal (Rock Crystal)
Quartz (Silicon Dioxide, SiO2)
Moqui Marble
Ironstone Concretion (Goethite/Hematite shell with Sandstone core)
Septarian Nodule (Dragon Stone)
Septarian Concretion (CaCO3 + CaMg(CO3)2 + SiO2)
Ironstone Concretion (Limonite/Goethite)
Iron oxide concretion (contains FeO(OH)·nH2O)
Moqui Marble
Iron Oxide Concretion (Limonite/Hematite over Sandstone)
Ironstone Concretion (Pot Stone)
Siderite or Limonite Concretion (FeCO3 or FeO(OH)·nH2O)
Moqui Marble
Iron Oxide Concretion (Hematite/Goethite-cemented Sandstone)
Agate (Moss or Plume Agate variety)
Silicon Dioxide (SiO2)
Polished Basalt
Basalt (Mafic volcanic rock)
Pink Granite
Phaneritic Felsic Intrusive Igneous Rock
Selenite
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
Gneiss
Gneiss (High-grade metamorphic rock)
Gneiss
Gneiss (High-grade Metamorphic Rock)
Pink Granite
Phaneritic Felsic Igneous Rock (Rich in K-Feldspar)
Granitic Pegmatite
Granite Pegmatite (coarse-grained intrusive igneous rock)
Gneiss
Gneiss
Moss Agate
Chalcedony (Silicon Dioxide / SiO2)
Ironstone Concretion (Limonite/Goethite)
Ferruginous Sandstone / Ironstone (FeO(OH)·nH2O)
Bog Iron / Limonite Concretion
Goethite/Limonite mixture (FeO(OH)·nH2O)
Emerald in Matrix
Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Agate (Lace Agate Geode Slice)
Silicon Dioxide (SiO2)
Granite (with Almandine Garnet inclusions)
Granite composed primarily of Quartz (SiO2), K-Feldspar (KAlSi3O8), and Almandine Garnet (Fe3Al2(SiO4)3)