Opal
Hydrated Silica (SiO2·nH2O)
mineral
Category
Sedimentary (Fossilized Organic Matter)
Browse sedimentary (fossilized organic matter) specimens identified by the Rock Identifier community.
Conglomerate
Polymictic Conglomerate
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Limonite (Ironstone)
Hydrated Iron Oxide (FeO(OH)·nH2O)
mineral
Sandstone
Arenite (SiO2 primarily)
sedimentary
Fossiliferous Limestone
Calcium Carbonate (CaCO3) with Bioclastic inclusions
sedimentary
Ironstone Concretion / Limonite
Goethite and Limonite (FeO(OH)·nH2O)
sedimentary
Quartz-veined Sedimentary Rock
Hydrothermally veined Clastic Sedimentary Rock (SiO2 veins in Matrix)
sedimentary
Chert (and associated Sedimentary rocks)
Microcrystalline Silica (SiO2)
sedimentary
Sandstone (Quartzose)
Arenite (Siliciclastic sedimentary rock)
sedimentary
Ambergris
Physeter macrocephalus excreta (Ambergris)
mineraloid / organic geological find
Conglomerate
Conglomerate (a clastic sedimentary rock)
Sedimentary Rock
Sandstone (Quartzite-rich)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Sandstone (lithic wacke/arenite)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Sandstone (likely Graywacke or Arkose variant)
Clastic Sedimentary Rock (SiO2 based)
sedimentary
Green Calcite
Calcium Carbonate (CaCO3)
mineral
Chert (Jasper)
Silicon Dioxide (SiO2)
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Sandstone
Arenite (Siliclastic Sedimentary Rock)
sedimentary
Sandstone (Quartzose)
Arenite (composed primarily of SiO2)
sedimentary
Gneiss
Gneiss (High-grade Metamorphic Rock)
metamorphic
Fossiliferous Limestone
Limestone with fossil inclusions (CaCO3)
sedimentary
Sandstone (Yellow/Tan Sandstone)
Arenite (primarily Quartz, SiO2)
sedimentary
Sandstone
Sandstone (lithified arenite/wacke)
Sedimentary Rock
Jasper
Silicon dioxide (SiO2)
sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with goethite or iron oxide inclusions
sedimentary
Sandstone (Weathered Cobble)
Clastic Sedimentary Rock (primarily SiO2)
sedimentary
Siltstone
Siltstone (primarily SiO2, Al2O3)
sedimentary
Dalmatian Stone (Dalmatian Jasper)
Peralkaline Quartz-Feldspar Rock with Arfvedsonite
igneous
Conglomerate
Conglomerate (a clastic sedimentary rock)
Sedimentary
Conglomerate (Puddingstone)
Conglomerate (specifically, clastic sedimentary rock)
Sedimentary
Blue Calcite
Calcium Carbonate (CaCO3)
mineral
Satin Spar (Selenite variant)
Gypsum (Calcium Sulfate Dihydrate, CaSO4·2H2O)
mineral
Firewood (Wood Log)
Lignum (Plant tissue composed of cellulose and lignin)
Organic (Non-geological)
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily Quartz with Limonite/Goethite staining)
sedimentary
Amethyst Geode
Amethyst (Silicon Dioxide), Formula: SiO2
mineral
River Rocks (Basalt and Sedimentary Stones)
Mafic Igneous Rock (Basalt) and Clastic Sedimentary Rock
igneous and sedimentary
Sandstone (Ferruginous)
Arenite (SiO2 with iron oxide impurities)
sedimentary
Limestone (specifically a Crushed Aggregate fragment)
Calcium Carbonate (CaCO3)
sedimentary
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
sedimentary
Sandstone (Quartz-rich)
Arenite (primarily SiO2)
sedimentary