Green Opal
Hydrated Silica (SiO2·nH2O)
mineraloid
Category
Anthropogenic Sedimentary Style Organic Solid
Browse anthropogenic sedimentary style organic solid specimens identified by the Rock Identifier community.
Learn about Anthropogenic Sedimentary Style Organic Solid in the encyclopedia
View all →
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Fossilized Shell Fragment
Invertebrate marine fossil, likely calcium carbonate replacement
fossil
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Sandstone (Pebble)
Sandstone (SiO2 dominated with minor feldspar/clay)
sedimentary
Quartz Geode
Crystalline Silicon Dioxide (SiO2) in a Geodic Concretion
mineral
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Druzy Quartz on Ironstone
Silicon Dioxide (SiO2) on Limonitic Ironstone
mineral
Weathered iron-rich sandstone or laterite fragment
Ferruginous sandstone, chiefly quartz (SiO₂) cemented or stained by iron oxides/hydroxides
sedimentary
Unopened Geode
Geode (containing various mineralization like Quartz SiO2)
sedimentary
Quartz Geode
Crystalline Silicon Dioxide (SiO2)
mineral
Conglomeratic gravel / polymictic breccia
Polymictic rudite, likely anthropogenic or beach/stream gravel; composition varies
sedimentary
Fossiliferous Sandstone (with Quartz patch)
Sedimentary Sandstone with Silicified Shell Fragments
sedimentary
Sandstone (Quartzite texture)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Grooved Maun Ball (Maul/Hammerstone-like Concretion)
Calcareous/Ferruginous Concretion in Sandstone Matrix
sedimentary
Red jasper (iron-rich chert), possibly weathered hematite-rich material
Jasper: microcrystalline quartz (SiO₂) with iron-oxide inclusions; hematite: Fe₂O₃
mineral
Limonite-stained Chert/Jasper
Microcrystalline Quartz (SiO2) with Iron Oxides (FeO(OH)·nH2O)
sedimentary
Limonite/Goethite Concretion
Hydrated Iron(III) Oxide-hydroxide (FeO(OH)·nH2O)
sedimentary
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Dendritic Agate
Dendritic Agate (Silicon Dioxide with Manganese or Iron Oxide inclusions, SiO2)
mineral
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Quartz Geode (Cracked Open Fragment)
Silicon Dioxide (SiO2)
mineral
Garnet-bearing Schist
Almandine Garnet (Fe3Al2(SiO4)3) in Mica Schist
metamorphic
Black Opal (Triplet)
Hydrated Silica (SiO2·nH2O)
mineral
Siltstone / Shale River Rock
Siltstone (primarily SiO2 with Al2O3)
sedimentary
Quartz Geode (Druzy)
Crystalline Silicon Dioxide (SiO2)
mineral
Red Jasper
Silicon Dioxide (SiO2) with Hematite (Fe2O3) inclusions
sedimentary
Diamond Drill Core (Greenschist and Quartzite)
Chlorite Schist / Meta-quartzite (Metamorphic Rock Core Sample)
metamorphic
Sandstone
Arenite (SiO2 based)
sedimentary
River Stone (likely Siltstone or fine-grained Basalt)
Clastic Sedimentary (Siltstone) or Mafic Igneous (Basalt)
sedimentary or igneous
Asphalt (Bituminous Concrete)
Asphaltum / Bitumen-Aggregate Matrix
Technonatural composite (often containing sedimentary/igneous aggregate)
Quartz (likely Herkimer Diamond style)
Silicon Dioxide (SiO2)
mineral
Quartz Geode
Silicon Dioxide (SiO2)
sedimentary
Opal cabochon or opal-like decorative specimen
Hydrated amorphous silica, SiO₂·nH₂O; likely synthetic or assembled opal material
gemstone
Black Onyx
Chalcedony (Silicon Dioxide - SiO2)
mineral
Chalcedony (Agate Pebble)
Microcrystalline Quartz (SiO2)
sedimentary
River Cobbles (Basalt, Quartzite, and Sandstone mix)
Fluvial detritus (primarily SiO2, Plagioclase, and Pyroxene mix)
Mixed: Igneous and Sedimentary
Quartz Geode
Crystalline Silicon Dioxide (SiO2)
mineral
Fossil Belemnite Guard
Belemnitella spp. (rostrum)
fossil