Red Sandstone
Sandstone (Quartz Arenite / Arkose with Hematite cement)
Category
Browse organic mineral specimens identified by the Rock Identifier community.
Red Sandstone
Sandstone (Quartz Arenite / Arkose with Hematite cement)
Ironstone Concretion
Ironstone (primarily Siderite or Limonite)
Black Shale
Argillaceous Chert/Shale
Jasper
Silicon dioxide (SiO2)
Bivalve Fossil (Internal Mold/Steinkern)
Class Bivalvia (Fossilized Mold)
Chert / Flint
Silicon Dioxide (SiO2)
Polished amber-colored stone, possibly chert or jasper
Uncertain from image; likely microcrystalline quartz (SiO₂) if chert/jasper
Amber
Succiniferous fossil resin (C10H16O)
Geode (Unopened)
SiO2 (Quartz-filled Sedimentary Nodule)
Shale with Pyrite
Clastic sedimentary rock containing Iron Disulfide (FeS2)
Pitted Limestone
Calcium Carbonate (CaCO3)
Pink Opal
Hydrated silica (SiO2 "n H2O)
Green Moss Agate
Agate (Silicon Dioxide - SiO2 with inclusions of Manganese/Iron oxides)
Fossilized Dinosaur Skull (Tyrannosaurus rex)
Tyrannosaurus rex (permineralized fossil), rich in Hydroxylapatite/Silica
Sandstone (Glauconitic)
Glauconitic Quartz Sandstone (SiO2 + (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)
Seashell Fragment
Calcium carbonate (CaCO3) - primarily Aragonite or Calcite
Siltstone with Fossil Cast
Sedimentary Rock (Siltstone / Fine-grained Sandstone)
Jasper
Silicon Dioxide (Microcrystalline Quartz, $SiO_2$)
Chert Nodule / Ironstone Concretion
Microcrystalline Quartz (SiO2) with Iron Oxides
Gray River Pebble (likely Limestone or Siltstone)
Sedimentary Rock (Calcium Carbonate or Siliciclastic)
Chert (with Epidote/Quartz veining)
Cryptocrystalline silica (SiO2) with Epidote/Quartz inclusions
Turquoise and Spiny Oyster (Heishi style beads)
Turquoise (CuAl6(PO4)4(OH)8·4H2O) and Spondylus (Spiny Oyster shell)
Sandstone (likely Fossiliferous Sandstone)
Clastic sedimentary rock (primarily SiO2)
Fancy Jasper
Jasper (Cryptocrystalline Quartz, SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Chert (Jasper)
Silicon Dioxide (SiO2)
Ferruginous Quartz
Silicon Dioxide (SiO2) with Hematite/Limonite impurities
Yellow Jasper
Quartz (Silicon Dioxide, SiO2 with impurities)
Fossilized Coprolite
Coprolite (fossilized feces)
Petrified Wood
Silicified Wood (mainly Quartz / SiO2)
Weathered River Rock (likely Chert or Basalt with algae)
Silicon dioxide (SiO2) with organic biofilm
Mammoth or Mastodon Tooth Fragment
Mammuthus / Mammut molar fragment
Fossilized Shark Tooth
Carcharodon carcharias (fossilized) / Hydroxyapatite permineralized with silica or iron
Petrified Wood
Silicified Wood (SiO2)
Chalcedony (Agate / Jasper Specimen)
Silicon Dioxide (SiO2)
Pyrite in Slate or Shale
Iron Sulfide (FeS2) in Argillaceous Matrix
Shungite
Shungite (carbon-rich Precambrian rock)
Pyrite
Iron Sulfide (FeS2)
Shungite
Shungite (carbon-rich Precambrian mineraloid)
Pyrite
Iron Sulfide (FeS2)
Chert (or Limestone)
Sedimentary Cryptocrystalline Quartz (SiO2) or Calcium Carbonate (CaCO3)
Chert (often called Flint)
Silicon Dioxide (SiO2)