Coral Fossil (Agatized Coral or Petoskey Stone)
Hexagonaria percarinata (if Petoskey) or generally Scleractinia (Agatized Coral)
Sedimentary/Fossil
Category
Mineral (Silicate Replaced Organic Material)
Browse mineral (silicate replaced organic material) specimens identified by the Rock Identifier community.
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Stromatolite (Jasper-replaced)
Fossilized Stromatolite (Cyanobacteria / Cryptozon / Silica SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Chert (Flint)
Chert (SiO2)
sedimentary
Fossilized Shark Tooth
Elasmobranchii dentition (calcium phosphate / hydroxyapatite)
fossil
Green Jasper
Silicon Dioxide (SiO2) with impurities of iron(II) silicate
sedimentary
Banded chert or flint
Microcrystalline quartz (SiO₂), likely with iron-oxide and dark organic/mineral impurities
sedimentary
Jasper
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Rough Chalcedony / Jasper Agate Nodule
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified wood (Quartz/Chalcedony/Opal)
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Mixed Quartz and Jasper Pebbles
Silicon Dioxide (SiO2)
Mineral
Fossil Shark Tooth
Lamniformes (order) - likely Cretalamna or Carcharias species
fossil
Chert (Common Opal/Jasper mix)
Silicon Dioxide (SiO2) with impurities
sedimentary
Chert Nodules (with Flint core)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (concretionary/nodular variant)
Microcrystalline Quartz (SiO2) with possible fossil or mineral inclusions
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Jasper
Microcrystalline quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Petrified Wood
Silicified Wood (Quartzo-feldspathic fossil wood)
fossil
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Fossil Shark Tooth
Chondrichthyes (Class)
fossil
Petrified Wood
Silicon Dioxide Fossilized Wood (SiO2)
fossil
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Megalodon Shark Tooth (Partial Fossil)
Otodus megalodon (fossilized in Calcium Phosphate/Apatite)
Mineral/Fossil
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Chert (containing Flint and Calcareous inclusions)
Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3) impurities
sedimentary
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Chert (varieties include Flint or Jasper)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Fossilized Shark Tooth
Scapanorhynchus (Sand Tiger Shark relative)
sedimentary
Crinoid Stem Fossil (Indian Bead)
Crinoid ossicle (Echinodermata)
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Tumbled Jasper and Tiger's Eye
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Petrified Wood
Silicified Wood (primarily Chalcedony/Quartz, SiO2)
fossil
Chert Nodules in Sedimentary Rock
Microcrystalline Quartz (SiO2) within Clastic Matrix
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
mineral
Petrified Wood
Silicified Wood (SiO2)
mineral