Fossil Shark Tooth
Odontaspididae (likely Carcharias sp.)
fossil
Category
Organic Mineraloid And Mineral
Browse organic mineraloid and mineral specimens identified by the Rock Identifier community.
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Petrified Bone Pebble
Silicified Fossilized Bone
fossil
Fossilized Crab Carapace (Concretion)
Decapoda (fossil), typically preserved in calcite or siderite concretion
sedimentary
Glauconite (Greensand)
(K, Na)(Fe3⁰, Al, Mg)₂(Si, Al)₄O₁₀(OH)₂
sedimentary
Chert (Nodule)
Silicon Dioxide (SiO2)
sedimentary
Moqui Marbles
Iron Oxide Concretion (Hematite/Goethite)
sedimentary
Petrified Wood
Silicified wood (primarily SiO2)
sedimentary
Petrified Wood
Silicified wood (primarily SiO2)
metamorphic
Chert (Jasper)
Silicon Dioxide (SiO2)
sedimentary
Fossilized Oyster Shell (Limestone/Coquina)
Crassostrea (Fossilized Bivalve), Calcium Carbonate (CaCO3)
sedimentary
Petrified Wood
Silicified wood (Quartz, Chalcedony, or Opal)
sedimentary
Vesicular basalt (likely weathered volcanic rock)
Basalt, commonly composed of plagioclase, pyroxene, and olivine
igneous
Jasper
Microcrystalline Quartz (SiO2)
gemstone
Amber
Fossilized Tree Resin
gemstone
Moss Agate
Silicon Dioxide (SiO2) with mineral inclusions of hornblende or chlorite
Mineral (variety of Chalcedony)
Fossilized Wood (Petrified Wood) and Associated Rocks
Silicified Wood / Xylopal
fossil
Megalodon Shark Tooth (Partial Fossil)
Otodus megalodon (fossilized in Calcium Phosphate/Apatite)
Mineral/Fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Dendritic Agate (or Dendritic Opal)
SiO2 (for Agate), SiO2·nH2O (for Opal)
Mineral
Banded Jasper
Silicate Mineral (Microcrystalline Quartz / SiO2)
sedimentary
Petrified Wood
Silicified Wood (Silicon Dioxide - SiO2)
fossil
Fossilized Bone (Petrified Bone)
Permineralized Vertebrate Remains
sedimentary
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Coal (Anthracite / Bituminous)
Organic Sedimentary Rock (Carbon-based)
sedimentary
Petrified wood
Silicified wood, commonly quartz/chalcedony (SiO₂) replacing wood tissue
fossil
Pyrite
Iron Sulfide (FeS2)
mineral
Pearl
Calcium Carbonate (Aragonite/Calcite) with Conchiolin (CaCO3)
mineral
Pyrite Geode
Iron Disulfide (FeS2)
mineral
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Shungite
Non-crystalline carbon (C)
mineral
Precious Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
mineral
Jasper Agate
Silicon dioxide (SiO2)
mineral
Chalcedony (Common Opal variant)
Silicon dioxide (SiO2) with varying levels of hydration
mineral
Educational Geologic Collection
Mixed Mineral and Rock Collection (Various compositions)
mineral
Moss Agate
Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxide
mineral
Tumbled chalcedony (likely moss or dendritic agate)
Microcrystalline quartz, SiO₂, with iron-oxide inclusions
mineral
Fossilized Horn Coral
Order Rugosa (Rugose Coral)
sedimentary
Quartz and Limestone Grouping
Silicon Dioxide (SiO2) / Calcium Carbonate (CaCO3)
mineral
Red Jasper
Silicon Dioxide (SiO2) with Iron Oxide inclusions
sedimentary
Limestone (Travertine/Tufa variant)
Calcium Carbonate (CaCO3)
sedimentary
Chert (Arrowhead Preform or Flake)
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary