Sandstone
Arenicola (comprising mostly Quartz, SiO2)
sedimentary
Category
Organic Specimen (Fossil)
Browse organic specimen (fossil) specimens identified by the Rock Identifier community.
Learn about Organic Specimen (Fossil) in the encyclopedia
View all →
Chert (vuggy variety)
Microcrystalline silica (SiO2)
sedimentary
Petrified Wood
Silicified wood (Quartz replacement)
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
sedimentary
Petrified Palmwood
Palmoxylon (fossilized monocot xylem)
sedimentary
Fossilized Coral
Scleractinia (fossil order), primarily Calcium Carbonate (CaCO3)
sedimentary
Coquina and Oyster Fossil Rock
Coquina limestone (Calcium Carbonate, CaCO3) containing fossilized Crassostrea / bivalve shells
fossil
Fossiliferous Limestone
Bioclastic Limestone (with Brachiopod and Bivalve molds)
sedimentary
Fossilized Gastropod in Chert/Limestone
Internal mold of Gastropoda (Class) with CaCO3 or SiO2 mineral formula
sedimentary
Petrified Wood
Silicified wood (Quartz replacement of organic wood structure)
fossil
Petrified Wood
Silicified wood (Quartz / Chalcedony replacement of organic cellulose)
fossil
Amber
Succinite (specifically for Baltic amber); chemical formula approximately C10H16O
Mineraloid
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
sedimentary
Sandstone
Arenite (SiO2 based)
sedimentary
Amber
Succinite (Fossilized Tree Resin)
Organic Mineraloid
Fossilized Bone Fragment
Permineralized Vertebrate Bone (Hydrox yapatite replaced by Silica or Calcite)
sedimentary
Ammonite Fossil (Polished Half / Cleoniceras)
Ammonoidea (Subclass), often Cleoniceras genus; fossilized with Calcite (CaCO3) and Aragonite
Sedimentary
Chert (or Fossiliferous Limestone)
Microcrystalline Quartz (SiO2) / Calcium Carbonate (CaCO3)
sedimentary
Fossiliferous limestone, likely coral or shell fragment
Calcitic limestone (primarily CaCO₃), containing preserved marine bioclasts
fossil
Weathered chert or silicified limestone nodule
Microcrystalline quartz (SiO₂), possibly replacing limestone; exact identification requires testing
sedimentary
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Fossiliferous Limestone with Crinoid Stem Impression
Calcium Carbonate (CaCO3) matrix with Crinoidea fossil
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Fossiliferous Limestone
Calcite (CaCO3) Rich Bio-sedimentary Rock
sedimentary
Sandstone (Ferruginous)
Arenite with Iron Oxide cement (SiO2 + Fe2O3)
sedimentary
Weathered, porous limestone (probable fossiliferous limestone)
Calcite-rich limestone; predominantly CaCO₃
sedimentary
Sandstone
Arenite (SiO2 principal component)
sedimentary
Fossilized Coral (Petoskey Stone or similar Rugose Coral)
Hexagonaria percarinata (or similar Rugose/Tabulate coral)
fossil
Petoskey Stone
Hexagonaria percarinata
fossil
Bivalve Fossil (Clam)
Class Bivalvia, likely Mercenaria or similar genus
fossil
Ambergris (Marine Coprolite/Subfossil)
Marine organic coprolite / Ambergris (Physeter macrocephalus metabolite)
fossil
Chert (Nodule)
Silicon Dioxide (SiO2)
sedimentary
Petrified Wood
Silicified wood / Xylopal
fossil
Limestone (with possible Crinoid or Fossil Impression)
Calcium Carbonate (CaCO3) / Calcite
sedimentary
Chert / Flint Pebble with Fossil Cavity
Silicon Dioxide (SiO2)
sedimentary
Amber
Succinite (with approximate formula C10H16O)
mineraloid
Shale
Shale (Fine-grained clastic sedimentary rock)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Iron-rich concretion or weathered ironstone
Goethite–hematite limonite aggregate; commonly described as limonite or ironstone
sedimentary
Chert (Jasper influence)
Microcrystalline Quartz (SiO2)
sedimentary
Limestone
Sedimentary Rock (Primarily Calcium Carbonate, CaCO3)
sedimentary