Fossiliferous Limestone with Rugose Coral
Calcium Carbonate (CaCO3) featuring Rugosa (extinct order of solitary and colony corals)
Category
Browse organic (geological interest) specimens identified by the Rock Identifier community.
Fossiliferous Limestone with Rugose Coral
Calcium Carbonate (CaCO3) featuring Rugosa (extinct order of solitary and colony corals)
Moss Agate and Hematite
Silica (SiO2) with fibrous inclusions of Manganese or Iron; Hematite (Fe2O3)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Amber
Succinite (fossilized resin); C10H16O
Petrified Wood (Silicified Wood)
Silicified Wood / Silicon Dioxide (SiO2)
Picture Jasper
Silicon Dioxide (SiO2) with iron oxide and organic impurities
Hypersthene (or Enstatite/Ferrosilite)
Orthopyroxene series (Mg,Fe)SiO3 - specifically, historically hypersthene (intermediate member) now referred to as Enstatite (Mg-rich) or Ferrosilite (Fe-rich)
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Petrified Wood
Silicified Wood (primarily SiO₂ / Silicon Dioxide)
Chert (variations include Flint or Jasper)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Weathered chert or silicified limestone
Microcrystalline quartz (SiO₂), likely chert formed by silicification of carbonate rock
Petrified Wood
Silicified Wood (SiO2)
Ironstone Concretion / Goethite-Hematite Geode
Goethite / Hematite Concretion (Fe3O4 / FeO(OH) / Fe2O3)
Petrified Wood
Silicified Wood (SiO2)
Possible flint or black chert
Microcrystalline quartz (SiO₂), likely chert/flint
Tumbled yellow calcite
Calcite (CaCO₃), likely honey or lemon calcite
Turquoise-and-coral silver jewelry brooch
Turquoise: hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O; red cabochons appear to be coral, likely set in silver
Chert (Cherty Shale / Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Fossilized coral (likely honeycomb or branching coral)
Fossil coral; probable Scleractinia or Tabulata, composition mainly microcrystalline CaCO₃
Moss Agate
Silicon Dioxide (SiO2) with inclusions of manganese or iron oxides
Shale (with minor calcite veining)
Clastic sedimentary rock (primarily clay minerals and quartz)
Chert Nodule
Microcrystalline Quartz (SiO2)
Banded sandstone pebble
Lithified quartz–feldspar sandstone, likely ferruginous and carbonaceous laminae
Grey and White Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Jasper (Red-Brown)
Silicon Dioxide (SiO2) with Iron Oxide impurities
Chert (Quartz Variety)
Microcrystalline Silica (SiO2)
Chert (specifically Tan/Yellow Chert)
Chert (Microcrystalline or Cryptocrystalline Silica, SiO2)
Chert Nodule
Microcrystalline Quartz (SiO2)
Green Moss Agate
Agate (Silicon Dioxide - SiO2) with inclusions of hornblende or chlorite
Septarian Nodule or Mud Crack Fossil
Septarian Nodule (Concretion)
Iron Ore / Hematite / Ironstone Nodule
Hematite / Goethite (Fe2O3 / FeO(OH))
Chert Nodule in Limestone (Flint in Chalk)
SiO2 (Microcrystalline Quartz) in CaCO3 (Calcite)
Petrified Wood
Silicified Wood (primarily SiO2)
Fossil Brachiopod
Phylum Brachiopoda
Petrified Wood
Silicified Wood (primarily SiO2)
Red Jasper
Red Jasper (variety of Chalcedony, SiO₂)
Silty Shale or Mudstone
Siltstone/Mudstone (Clastic Sedimentary Rock)
Weathered gray-green rock fragment
Likely shale or mudstone; exact identification requires testing
Tumbled chert or flint
Microcrystalline quartz (SiO₂), likely brown chert/flint