Fossil Shark Tooth
Otodus sp. (likely Otodus obliquus) fossil
fossil
Category
Mineral (Silicate Replaced Organic Material)
Browse mineral (silicate replaced organic material) specimens identified by the Rock Identifier community.
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Chert (often called Flint when in chalk or limestone)
Silicon Dioxide (SiO₂)
sedimentary
Seashell Fossil
Invertebrate fossil (phylum Mollusca)
fossil
Fine-grained brown sand or weathered soil
Unconsolidated siliciclastic sediment, likely quartz-rich sand (SiO₂) mixed with iron-oxide-coated grains
sedimentary
Carved pyrite frog or toad
Pyrite (iron disulfide, FeS₂), likely a carved massive aggregate
mineral
Petrified Wood
Silicified Wood (SiO2)
fossil
Petrified Wood
Silicified Wood (primarily SiO₂)
sedimentary
Chert (varietal Flint)
Chert (SiO2)
sedimentary
Chert with Weathered Rind (Flint/Chalcedony)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (River Pebble)
Microcrystalline silica (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified wood (Quartz/Chalcedony replacement of cellulose)
fossil
Coral Fossil (Petrified Coral)
Scleractinia (Order) - Calcified Fossil Skeleton (CaCO3)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood (Silicified Fossil)
Silicified Wood (SiO2)
sedimentary
Banded chert or flint
Microcrystalline quartz (SiO₂), likely with iron-oxide and dark organic/mineral impurities
sedimentary
Fossilized coral or silicified organic limestone
Likely fossil coral (Scleractinia/Tabulata) replaced or cemented by calcite and silica; exact identification requires close examination
fossil
Red Jasper
Microcrystalline Quartz (Chalcedony), SiO2 with iron oxide inclusions
sedimentary
Jasper with Quartz Vein
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Petrified Wood
Silicified Wood (SiO2 - Silicon Dioxide)
mineral
Petrified Wood
Silicified wood (SiO2)
fossil
Chert (Flint)
SiO2 (Microcrystalline Quartz)
sedimentary
Coral Fossil (Agatized Coral or Petoskey Stone)
Hexagonaria percarinata (if Petoskey) or generally Scleractinia (Agatized Coral)
Sedimentary/Fossil
Petrified wood
Silicified wood; commonly quartz/chalcedony (SiO₂) replacing organic tissue
fossil
Chert (with Limestone/Dolomite host)
Microcrystalline Quartz (SiO2)
sedimentary
Green Jasper
Silicon Dioxide (SiO2) with impurities of iron(II) silicate
sedimentary
Yellow Jasper
Silicon Dioxide (SiO2)
mineral
Fossil Shell (Bivalve)
Phylum Mollusca, Class Bivalvia (typically composed of Calcium Carbonate / CaCO3)
sedimentary
Banded agate (likely petrified wood or silicified sediment)
Microcrystalline quartz/chalcedony, SiO₂; possible silicified wood
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Chert
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Jasper
Silicon dioxide (SiO2) with impurities
sedimentary
Polished ocean jasper (orbicular jasper), probable
Microcrystalline quartz/chalcedony (SiO₂) with iron-oxide and other mineral inclusions
mineral
Sand Tiger Shark Tooth Fossil
Carcharias taurus (fossilized tooth)
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary