Petrified Wood
Silicified Wood (SiO2)
fossil
Category
Sedimentary (Fossilized Organic Remain)
Browse sedimentary (fossilized organic remain) specimens identified by the Rock Identifier community.
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Fossil Coral (Petoskey Stone / Rugose Coral)
Hexagonaria percarinata (or similar fossilized rugose/tabulate coral)
fossil
Fossil Sand Dollar (Echinoidea)
Phylum Echinodermata, Class Echinoidea (likely Dendraster or Scutella)
sedimentary
Polished septarian nodule
Calcite–aragonite cemented carbonate concretion, commonly with clay minerals and iron oxides
sedimentary
Quartzite Cobble
Quartzite (SiO2)
metamorphic
Quartzite
Quartzite
metamorphic
Lake Superior Agate
Silicon Dioxide (SiO2) with iron impurities
mineral
Quartzite
Quartzite (SiO2)
metamorphic
Quartzite pebble
Quartzite (SiO2)
metamorphic
Coquina or Fossilized Shell Fragment
Calcium Carbonate (CaCO3) / Biogenic Limestone
sedimentary
Brachiopod Fossil in Matrix
Phylum Brachiopoda
fossil
Fulgurite
Lechatelierite
mineral
Vesicular Basalt (or Rhyolite)
Extrusive Igneous Rock with Vesicular Texture
igneous
Petoskey Stone
Hexagonaria percarinata
fossil
Crinoid Marble (Fossilized Limestone)
Crinoidal Limestone (comprising Calcite/Aragonite CaCO3)
sedimentary
Granite Porphyry
Phaneritic-Porphyritic Igneous Rock
igneous
Smoky Quartz (Apache Tear Variety)
Silicon dioxide (SiO2) - Volcanic Glass
igneous
Porphyritic Basalt
Basalt with plagioclase phenocrysts
igneous
Script Jasper
Silicon Dioxide (SiO2) with impurities
sedimentary
Gold Sheen Obsidian
Volcanic Glass (SiO2 + impurities)
igneous
Quartzite River Rock
Quartzite (SiO2 based metamorphic rock)
metamorphic
Quartzite River Stone
Quartzite (primarily SiO2)
metamorphic
Apache Tear
Obsidian (Hydrated Volcanic Glass - SiO2)
igneous
Rutilated quartz bead bracelet
Quartz, silicon dioxide (SiO₂), with rutile inclusions (TiO₂)
mineral
Sandstone with trace fossil
Sandstone, possibly with Skolithos or similar trace fossil
sedimentary
Fossil Coral (Rugose Coral / Horn Coral fragment)
Rugosa (Tetracoralla) / Calcite (CaCO3)
fossil
Fossilized Sea Urchin (Echinoid)
Echinoidea (Class) - likely replaced by Calcite or Quartz
sedimentary
Conical fossil shell or shell fragment
Likely a gastropod shell fragment; exact taxon indeterminate from the image
fossil
Fossilized trilobite
Trilobita; likely an enrolled asaphid or phacopid trilobite
fossil
Fossilized ammonite
Ammonoidea (likely a ribbed Jurassic–Cretaceous ammonite), replaced mainly by calcite or silica
fossil
Fossilized Coral
Rugosa or Tabulate Coral Fossil (Replacement by Silica/Calcite)
fossil
Fossilized Brachiopod
Brachiopoda (likely Order Spiriferida or Productida)
fossil
Petoskey Stone
Hexagonaria percarinata
fossil
Echinoid Fossil (Sea Urchin Fossil)
Echinoidea
fossil
Fulgurite
Fulgurite (Lechatelierite or fused sand/quartz)
mineral
Dendritic Opal
Dendritic Common Opal (SiO2·nH2O with Manganese oxide inclusions)
mineral
Rugose Coral (Horn Coral) Fossil in Limestone
Order Rugosa (commonly Grewingkia or Zaphrentis genus)
sedimentary
Petoskey Stone (Hexagonaria coral fossil)
Hexagonaria percarinata
sedimentary
Porphyry
Porphyritic Andesite/Basalt
igneous
Petoskey Stone
Hexagonaria percarinata (Silicified/Calcitic)
fossil
Fossilized Coral (Rugose Coral / Horn Coral)
Rugosa / Scleractinia
fossil
Fossilized Echinoid (Sea Urchin)
Echinoidea (Class), often found as calcitic fossils
sedimentary