Greywacke (River Pebble)
Dirty Sandstone (SiO2 with lithic fragments)
sedimentary
Category
Sedimentary (Biogenic Sediment Or Biological Remain)
Browse sedimentary (biogenic sediment or biological remain) specimens identified by the Rock Identifier community.
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Weathered chert or flint nodule
Microcrystalline quartz (SiO₂), commonly with chalcedony and minor iron oxides
sedimentary
Ironstone Concretion / Limonite-stained Siltstone
Ironstone (primarily Limonite FeO(OH)·nH2O and Siltstone)
sedimentary
River Pebble (Gravel Pebble)
Stream-rounded Rock / Siliciclastic Pebble
sedimentary
River Pebble
Siliceous rock fragment
sedimentary
Chert Conglomerate (or Breccia)
Sedimentary Clastic Rock (variety: Ferruginous Chert Breccia)
sedimentary
Sandstone Pebble
Arenite (SiO2 based)
sedimentary
Glauconitic Sandstone
Greensand (Glauconite-bearing sandstone)
sedimentary
Conglomerate
Clastic Sedimentary Rock (Conglomerate)
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
River Stone (likely Andesite or Siltstone)
Intermediate Volcanic Rock / Fine-grained Sedimentary Rock
igneous
River Stone (Basalt or Siltstone)
Mafic Volcanic Rock or Clastic Sedimentary Rock
igneous or sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
mineral
Concretion
Septarian Concretion
sedimentary
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Gastropod Fossil (Snail Steinkern)
Class Gastropoda fossil, composed of Calcium Carbonate (CaCO3)
sedimentary
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
sedimentary
Fossil Coral
Scleractinia (Anthos), primarily Calcium Carbonate (CaCO3)
sedimentary
Ironstone Concretion (likely)
Goethite/Hematite/Limonite cemented sediment
Sedimentary Rock
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Bivalve Fossil (Brachiopod or Scallop)
Class Bivalvia (or potentially Phylum Brachiopoda)
fossil
Fossilized Brachiopod
Phylum Brachiopoda (likely Order Spiriferida or Orthida)
fossil
Green Jasper
Quartz (Silicon Dioxide, SiO2) with iron silicate inclusions
sedimentary
Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Fossilized Brachiopod
Phylum Brachiopoda
fossil
Fossilized Bivalve Shell
Class Bivalvia (fossilized)
fossil
Starfish Fossil
Asteroidea fossil
fossil
Fossiliferous Limestone with Rugose Coral
Calcite (CaCO3) matrix containing Rugosa (order of extinct solitary and colonial corals)
sedimentary
Fossilized Gastropod Steinkern
Class Gastropoda internal mold
fossil
Ironstone Concretion
Ferruginous Concretion
sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Iron inclusions
sedimentary
Light-colored chert or weathered limestone
Microcrystalline quartz (SiO₂) or calcitic limestone (CaCO₃); exact identification requires testing
sedimentary
Sandstone Concretion
Carbonate-cemented Sandstone Concretion
sedimentary
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Sandstone Chert Concretion
Silica-cemented Concretion (primarily SiO2)
sedimentary
Sandstone Concretion
Clastic Sedimentary Concretion (SiO2 with Iron Oxide)
sedimentary
Fossilized Turritella Gastropod (Internal Mold)
Turritella (Fossil Gastropod Crust)
sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Hematite impurities
sedimentary
Tumbled brown jasper pebble
Jasper, microcrystalline quartz (SiO₂), commonly with iron-oxide impurities
mineral
Fossilized Echinoid (Sea Urchin) or Brachiopod
Echinoidea / Invertebrate Fossil
fossil
Orthoceras Fossil in Limestone
Orthoceras regulare (Class Cephalopoda)
fossil
Fossil Sponge / Horn Coral / Crinoid Stem
Phylum Porifera or Cnidaria fossilized in calcium carbonate / silica
fossil