Sandstone
Arenite
Category
Browse anthropogenic sedimentary style organic solid specimens identified by the Rock Identifier community.
Sandstone
Arenite
Asphalt (Bituminous Concrete)
Asphaltum / Bitumen-Aggregate Matrix
Hematite Nodules (Moqui Marbles style)
Iron Oxide (Fe2O3)
Opal
Hydrated Silica (SiO2·nH2O)
Agate Geode / Nodular Chalcedony
Silicon Dioxide (SiO2) with impurities
Grooved Maun Ball (Maul/Hammerstone-like Concretion)
Calcareous/Ferruginous Concretion in Sandstone Matrix
Native Sulfur
Sulfur (S8)
Microcrystalline Limestone Pebble
Carbonate sedimentary rock (Calcium Carbonate, CaCO3)
Jasper (Milky/Cream Variety)
Silicon Dioxide (SiO2) - variety of Chalcedony
Ocean Jasper (Orbicular Jasper)
Silicon Dioxide (SiO2) with iron and other impurities
Concrete
Anthropogenic Sedimentary Conglomerate (Cement mixture: typically Ca2SiO4, Ca3SiO5, Ca3Al2O6)
White Agate (Chalcedony)
Agate (Silicon Dioxide - SiO2)
Geode (Unopened)
Siliceous Concretion / Geode
Geode (Quartz)
Silicon Dioxide (SiO2)
Precious Opal
Hydrated Silica (SiO2·nH2O)
Yellow Jasper
Silicon Dioxide with Iron inclusions (SiO2)
Agate (Common Chalcedony)
Silicon Dioxide (SiO2)
Quartz (likely Herkimer Diamond style)
Silicon Dioxide (SiO2)
Pearls
Aragonite (calcium carbonate) and Conchiolin
Banded Gneiss
Gneiss (quartz-feldspar-biotite metamorphic rock)
Fired Clay Brick (Anthropic Rock substitute)
Anthropogenic polycrystalline ceramic (predominantly Mullite and Quartz: Al6Si2O13 + SiO2)
Quartz Geode
Silicon Dioxide (SiO2) in a Secondary Formation
Jasper (Willow Creek/Desert style)
Silicon Dioxide (SiO2) with iron and clay impurities
Quartz Geode (Nodule)
Silicon Dioxide (SiO2)
Wonderstone (Liesegang Sandstone)
Silicified Sandstone with Liesegang Rings (SiO2 + FeO(OH))
Quartzite Pebble (River Rock)
Metamorphic Quartzite (predominantly SiO2)
Quartz Geode
Silicon Dioxide (SiO₂)
Sandstone
Quartz Sandstone (predominantly)
Yellow Chalcedony (Carnelian/Yellow Agate)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Opal
Hydrated amorphous silica (SiO2·nH2O)
Red Jasper (River Pebble)
Silicon Dioxide (SiO2) with hematite impurities
Baroque Pearl (and potentially a small Sapphire/Blue Topaz)
Pearl: Calcium Carbonate (aragonite or calcite) with conchiolin. Sapphire: Aluminum Oxide (Al2O3). Blue Topaz: Al2SiO4(F,OH)2.
Pyrite in Shale
Iron Disulfide (FeS2)
Agate Geode
Cryptocrystalline Quartz (SiO2)
Quartz Geode
Silicon Dioxide (SiO2)
Agate Geode
Chalcedony (SiO2 - Silicon Dioxide)
Shale
Mudstone (composed primarily of clay minerals like kaolinite, illite, and smectite, with quartz and calcite)
Pyrite
Iron Sulfide (FeS2)
Limestone (specifically Bituminous or Carbonaceous Limestone)
Calcium Carbonate (CaCO3) with Organic Impurities
Fossiliferous Limestone with Rugose Coral
Calcite (CaCO3) matrix containing Rugosa (order of extinct solitary and colonial corals)
Coal (most likely Bituminous or Anthracite)
Coal (organic sedimentary rock)
Coal (likely Bituminous or Lignite)
Organic Sedimentary Rock (Carbonaceous)