Chert Concretion
Microcrystalline Quartz (SiO2)
Category
Browse sedimentary (fossilized organic matter) specimens identified by the Rock Identifier community.
Chert Concretion
Microcrystalline Quartz (SiO2)
Fossilized Rugose Coral (Horn Coral)
Order Rugosa
Shale (possibly Carbonaceous or Oil Shale)
Argillaceous Sedimentary Rock
Fossilized Shell in Limestone
Carbonate sedimentary rock with Bivalvia or Brachiopoda remains
Chert (Light Grey / Flint variant)
Cryptocrystalline Quartz (SiO2)
Fossilized bone fragment
Fossil bone, composed chiefly of carbonate-fluorapatite (bioapatite)
Tumbled amber-like chalcedony or resinous fossil material
Likely chalcedony (microcrystalline SiO₂), though the appearance could also indicate copal/amber
Likely bituminous coal
Coal, predominantly carbon-rich organic matter with variable maceral and mineral content
Quartz Geode
Silicon Dioxide (SiO2) in sedimentary host rock
Chert (Flint Nodules)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Quartz Geode
Silicon Dioxide (SiO2)
Red Jasper
Quartz (SiO2) with iron oxide inclusions
Dinosaur Skull Fossil (Velociraptor Replica)
Velociraptor mongoliensis fossil specimen in sedimentary matrix
Petrified Wood
Fossilized Wood (silicified wood)
Moss Agate
Silicon Dioxide (SiO2) with inclusions of manganese or iron oxide
Calcareous Tufa (or Travertine)
Calcium Carbonate (CaCO3)
Septarian Nodule (Micro-fragment)
Septarian Nodule / Concretion (CaCO3 + CaMg(CO3)2 + Quartz)
Fossilized Bone
Permineralized Vertebrate Bone
Fossiliferous Limestone (with Crinoids)
CaCO3 (Calcium Carbonate)
Petrified Wood (Agatized/Silicified Wood)
Silicified Paleoxylon (primarily SiO2)
Chert (specifically Blue Chert or Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Shale
Shale (clay-sized silicate minerals)
Petrified Wood
Silicified Wood (SiO2)
Pyritic Mudstone
Argillaceous rock (FeS2)
Amber
Succinite (approximate formula C10H16O)
Shale (with minor calcite veining)
Clastic sedimentary rock (primarily clay minerals and quartz)
Petrified Wood (Black / Carbonized)
Silicon Dioxide (Quartz/Chalcedony replacing Organic Matter)
Amber
Succinite (Fossilized Tree Resin)
Fossilized Shark Tooth (Partial) or Coprolite
Elasmobranchii (fossil) or Coprolite (trace fossil)
Pyrite
Pyrite (Iron sulfide, FeS₂)
Petrified Wood
Silicified Wood (primarily SiO2)
Banded chert or flint pebble
Microcrystalline quartz (chalcedony), SiO₂
Chert with Quartz Vein
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
Tree Agate (or Moss Agate), faceted into a crystal tower
Dendritic Agate (Silicon Dioxide, SiO2)
Fossiliferous Limestone
Biogenic Limestone (CaCO3 with fossil fragments)
Quartz Geode in Chert/Limestone Matrix
Silicon Dioxide (SiO2) within Sedimentary Host Rock
Fossilized Shark Tooth
Carcharodon carcharias (fossilized) / Hydroxyapatite permineralized with silica or iron
Shale or Siltstone
Sedimentary Clastic Rock (Variable mineral composition including quartz and clay minerals)
Chert (Brecciated Chert)
Silicon Dioxide (SiO2)
Polished fossiliferous limestone
Bioclastic carbonate rock, primarily calcite (CaCO₃)
Green Sandstone
Glauconitic Sandstone