Chert (v. Flint)
Sedimentary Cryptocrystalline Quartz (SiO2)
Category
Browse organic material (likely a fruit or berry) specimens identified by the Rock Identifier community.
Chert (v. Flint)
Sedimentary Cryptocrystalline Quartz (SiO2)
Quartzite with inclusions
Quartzite
Tumbled banded agate (likely chalcedony)
Microcrystalline quartz, SiO₂; probable banded chalcedony/agate
Chert (Jasper/Chalcedony variant)
Microcrystalline Quartz (SiO2)
Limestone with Fossil inclusions
Fossiliferous Limestone (CaCO3)
Chert (Jasper nodule)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Petrified Wood (Agatized/Silicified Wood)
Silicified Wood (SiO2)
Petrified Wood
Silicified wood (primarily SiO2)
Likely bituminous coal
Coal, predominantly maceral-rich carbonaceous material (composition varies)
Chert (often called Flint when dark or worked)
Cryptocrystalline silica (SiO2)
Tumbled yellow calcite
Calcite (CaCO₃), likely honey or lemon calcite
Chert (Flint with Iron Staining)
Silicon Dioxide (SiO2)
Banded Chert (Flint)
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified Paleoxylon (SiO2)
Jasper (Petrified Wood Variety)
Silicon Dioxide (SiO2)
Chert (Jasper variety)
Cryptocrystalline Quartz (SiO2)
Tumbled coral fragment (likely white calcitic coral)
Calcium carbonate, primarily aragonite or calcite (CaCO₃); exact coral genus cannot be determined from the image
Fossiliferous Limestone
Bioclastic Limestone
Honey calcite (likely)
Calcite, calcium carbonate (CaCO₃)
Fossil Shark Tooth
Otodus sp. (likely Otodus obliquus) fossil
Petrified Wood
Silicified wood (Quartz, Chalcedony, or Opal)
Chert (Gray Chalcedony)
Microcrystalline Quartz (SiO2)
Fossilized Megalodon Tooth Fragment
Otodus megalodon (Carcharocles megalodon fossil)
Tumbled brown agate (likely moss or plume agate)
Microcrystalline quartz, chiefly chalcedony (SiO₂), with iron-oxide and possibly mineral inclusions
Fossil Shark Tooth
Carcharadon sp. (likely Carcharodon carcharias or similar Lamniformes)
Sandstone (likely Fossilized Wood or Concrete Simulacrum)
Arenite / Silicified Wood / Anthropogenic Concrete
Iron-rich chert or jasper
Microcrystalline quartz (SiO₂), commonly colored by hematite/goethite
Chert (likely flint), possibly chalcedony-rich
Microcrystalline quartz, SiO₂ (quartz/chalcedony)
Chert / Flint
Chert (SiO2)
Weathered chert or silicified limestone
Microcrystalline quartz (SiO₂), likely chert formed by silicification of carbonate rock
Polished/tumbled calcite
Calcite (calcium carbonate, CaCO₃)
Chert (Yellow Jasper/Flint)
Microcrystalline Quartz (SiO2)
Fossil gastropod shell
Fossilized marine gastropod; exact genus/species requires locality and examination
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, SiO2)
Fossiliferous limestone
Bioclastic carbonate rock; predominantly calcite (CaCO₃)
Polished banded agate (likely picture jasper or petrified wood)
Microcrystalline quartz, SiO₂, with iron-oxide and clay inclusions
Carved pyrite frog or toad
Pyrite (iron disulfide, FeS₂), likely a carved massive aggregate
Chert (likely flint)
Microcrystalline quartz (SiO₂), chiefly chalcedony and quartz
Chert Pebble
Microcrystalline or cryptocrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood / Chalcedony (SiO2)
Petrified Wood (Silicified Wood)
Silicified Wood / Silicon Dioxide (SiO2)
Sedimentary Rock with Crafts (Pet Rock)
Sedimentary rock decorated with synthetic materials