Petrified Wood
Silicified Wood (primarily SiO₂)
sedimentary
Category
Organic Mineral
Browse organic mineral specimens identified by the Rock Identifier community.
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Ironstone Concretion (Limonite/Goethite)
Iron oxide concretion (contains FeO(OH)·nH2O)
sedimentary
Chert (Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Shale (or Mudstone)
Siltstone/Argillite (composed mainly of clay and silt-sized particles)
sedimentary
Chert (Jasper/Flint variant)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Flint)
Silicon dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Shale (with minor calcite veining)
Clastic sedimentary rock (primarily clay minerals and quartz)
sedimentary
Fossilized Bone / Dinosaur Fossil
Fossilized vertebrate bone (permineralized)
fossil
Fossilized Bivalve Shell
Bivalvia (Phylum Mollusca)
fossil
Chert (Nodule)
Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Flint)
Chert (Microcrystalline or cryptocrystalline Quartz, SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
mineral
Pearl
Calcium Carbonate (mostly Aragonite), CaCO3 (with conchiolin)
mineral
Pyrite in Limestone
Iron Sulfide (FeS2) in Calcium Carbonate (CaCO3)
mineral
Yellow Jasper
Silicon Dioxide (SiO2)
mineral
Chalcedony (Botryoidal or Tumbled)
Chalcedony (SiO₂)
mineral
Chert (Jasper/Flint Pebble)
Microcrystalline quartz (SiO2)
sedimentary
Mammoth or Mastodon Tooth Fragment
Mammuthus / Mammut molar fragment
fossil
Fossilized Coral
Rugosa / Scleractinia (Agatized or Calcitized Coral)
fossil
Moss Agate
Silicon Dioxide (SiO2) with inclusions
mineral
Shale
Fissile mudrock (composed primarily of clay minerals and quartz)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Moss Agate
Silicon Dioxide (SiO2) with inclusions
mineral
Petrified Wood
Silicified Wood / Chalcedony (SiO2)
mineral
Amber
Succinite (specifically for Baltic amber); Approximate formula: C10H16O
Organic Gemstone (Mineraloid)
Green Moss Agate
Silicon Dioxide (SiO2) with inclusions of hornblende or chlorite
sedimentary
Fossilized Shark Tooth
Chondrichthyes (class) fossilized tooth
fossil
Yellow Chert (Chert / Cryptocrystalline Quartz)
Silicon Dioxide (SiO2)
sedimentary
Chert (Flint variety)
Chert (SiO2)
sedimentary
Chert (varieties include Flint and Jasper)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Glauconite (Green Sandstone)
Glauconite (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2
sedimentary
Chert (Brecciated Chert)
Silicon Dioxide (SiO2)
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Nodular Chert)
Silicon Dioxide (SiO2)
sedimentary
Black Marble
Recrystallized Calcite (CaCO3)
metamorphic
Mammoth Tooth
Mammuthus tooth fossil
fossil
Jasper
Silicon dioxide (SiO2) with iron oxide inclusions
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Fossil Shark Tooth
Lamniform (Mackerel Shark) fossil tooth, likely Otodus or Cretalamna
fossil
Fossilized Shark Tooth
Elasmobranchii fossil (likely Odontaspididae family)
sedimentary
Petrified Wood
Silicified Wood (primarily Chalcedony or Quartz, SiO2)
sedimentary