Chert (Chalcedony/Agate variety)
Microcrystalline Quartz (SiO2)
Category
Browse sedimentary or igneous fragment specimens identified by the Rock Identifier community.
Chert (Chalcedony/Agate variety)
Microcrystalline Quartz (SiO2)
Chert (Tan/Buff variety)
Silicon Dioxide (SiO2)
Hematite
Iron(III) oxide (Fe2O3)
Weathered fossiliferous limestone fragment, possibly fossil coral or shell material
Indeterminate carbonate fossil in calcitic limestone; likely composed mainly of calcite (CaCO₃), but species identification is not possible from this image alone
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
Chert (Arrowheads)
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified wood (principally SiO2)
Lepidodendron fossil (Scale Tree Bark)
Lepidodendron (Lycophytina class)
Petrified Wood
Silicified wood (primarily Silicon Dioxide, SiO2)
Fossilized Coral
Scleractinia (fossil order), primarily Calcium Carbonate (CaCO3)
Petrified Wood (Silicified Fossil)
Silicified Wood (SiO2)
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (often called Flint or Jasper locally)
Chert (Microcrystalline Quartz, Formula: SiO2)
Sandstone
Arenite (SiO2 with Fe2O3)
Chert
Cryptocrystalline Quartz (SiO2)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Pyrite
Iron Sulfide (FeS2)
Graywacke
Argillaceous sandstone
Dalmation Stone (Dalmation Jasper)
Peralkaline rock (primarily Feldspar and Quartz with Arfvedsonite spots)
Chert (Black Chert or Flint)
Silicon Dioxide (SiO2)
Sandstone (Ferruginous)
Arenite with Iron-Oxide Cement (primarily SiO2 with Fe2O3/FeOOH)
Red Sandstone Pebble
Arenite with Hematite (Fe2O3) cement
Yellow calcite crystal cluster with calcite fragment
Calcite, calcium carbonate (CaCO₃)
Sandstone (lithic/arkosic)
Clastic sedimentary rock (primarily SiO2)
Mixed river gravel (alluvial conglomeratic sediment)
Polymictic alluvium; composition includes quartz, feldspar, chert, granite, basalt, and metamorphic rock fragments
Fossiliferous Limestone (Coquina / Shell Bed)
Biogenic Limestone (Calcium Carbonate, CaCO3)
Quartz
Silicon Dioxide (SiO2)
Pyrite on Quartz matrix
Iron Disulfide (FeS2) on Silicon Dioxide (SiO2)
Crushed Limestone
Calcium Carbonate (CaCO3)
Petrified Wood
Silicified Wood (SiO2)
Coral Fossil (Petrified Coral)
Scleractinia (Order) - Calcified Fossil Skeleton (CaCO3)
Fossilized Coral (Favosites)
Favosites (Extinct Tabulate Coral)
Chert (and Flint)
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Chert (Flint)
Chert (Cryptocrystalline Quartz, SiO2)
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Brown Variety)
Microcrystalline quartz (SiO2)
Chert (often called Flint for darker varieties)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Chert (specifically Green Chert/Jasper)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Calamites (Fossilized Horsetail)
Calamites suckowii (Family: Calamitaceae)
Fossil Coral
Scleractinia (fossil order), primarily Calcium Carbonate (CaCO3)
Chert (specifically Yellow or Brown Chert / Jasper)
Silicon Dioxide (SiO2)