Petrified Wood
Silicified Wood (SiO2)
Category
Browse organic (non geological) specimens identified by the Rock Identifier community.
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Fossil Shell (Bivalve)
Class Bivalvia (Likely a member of the Ostreidae or Gryphaeidae family), CaCO3
Quartzite
Quartzite (Metamorphosed quartz sandstone)
Man-made Synthetic Material (Plastic/Composite)
Acrylonitrile Butadiene Styrene (ABS) or High-Impact Polystyrene (HIPS)
Petrified Wood
Silicified wood (Quartz/Chalcedony/Opal)
Petrified Wood
Silicon Dioxide Fossilized Wood (SiO2)
Chert (Flint) with Limestone Matrix
Silicon Dioxide (SiO2) within Calcium Carbonate (CaCO3)
Quartzite
Quartzite (primarily SiO2)
Limestone (Crushed Gravel)
Limestone (Calcium Carbonate, CaCO3)
Obsidian
Volcanic Glass (SiO2)
Obsidian
Obsidian (Volcanic Glass)
Obsidian
Volcanic glass (SiO2-rich extrusive igneous rock)
Chert Nodule (with Geode cavity)
Cryptocrystalline Quartz (SiO2)
Iron-rich weathered rock or limonite/goethite nodule
Limonite (mixture dominated by goethite, FeO(OH)·nH₂O), possibly with quartz or clay
Obsidian
Obsidian (Volcanic Glass; SiO2 content > 70%)
Petrified Wood
Silicified Wood (primarily SiO2)
Geode (Unopened)
Silica-rich concretion (SiO2)
Dyed or treated turquoise-like tumbled stone
Likely turquoise (CuAl₆(PO₄)₄(OH)₈·4H₂O), though blue-green magnesite or howlite imitation is possible
Coquina
Biogenic Limestone (mostly Calcium Carbonate, CaCO3)
Black Obsidian
Volcanic Glass (felsic volcanic glass, rich in SiO2)
Chert (Jasper variation)
Silicon dioxide (SiO2) - Microcrystalline Quartz
Petrified Wood
Silicified wood (Quartz/Chalcedony/SiO2)
Fossiliferous Limestone
Biomicrite / Limestone with fossils
Fossilized Shark Tooth
Chondrichthyes (Class) fossil
Olive Sea Shell Fossil
Oliva sp. (Calcium Carbonate, CaCO3)
Ironstone Concretion
Goethite-rich Siltstone / Siderite (FeCO3)
Chert (Yellow Jasper variant)
Microcrystalline Quartz (SiO2)
Obsidian
Obsidian (principally SiO2)
Obsidian Arrowhead
Volcanic Glass (70% or more SiO2)
Amber
Succinite (Fossilized Tree Resin)
Chert (Flint Nodules)
Microcrystalline Quartz (SiO2)
Chert (and Fossilized Brachiopod shell)
Sedimentary Cryptocrystalline Quartz (SiO2)
Moss Agate
Chalcedony (Silicon Dioxide, SiO2) with inclusions
Obsidian
Volcanic Glass (predominantly SiO2)
Petrified Wood
Silicified wood (Quartz variant, SiO2)
Obsidian
Obsidian (Amorphous volcanic glass, SiO2 rich)
Obsidian
Volcanic glass (high silica SiO2)
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Jasper/Flint variant)
Silicon Dioxide (SiO2)
Chert (specifically Gray/Blue Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Graphite Schist
C (Carbonaceous Schist)