Anthracite Coal
Carbon (with trace impurities)
Category
Browse organic material specimens identified by the Rock Identifier community.
Anthracite Coal
Carbon (with trace impurities)
Limestone with Gastropod Fossil
Sedimentary Calcium Carbonate (CaCO3) with Gastropoda inclusion
Tumbled coral fragment (likely white calcitic coral)
Calcium carbonate, primarily aragonite or calcite (CaCO₃); exact coral genus cannot be determined from the image
Onyx (Black) and Mother of Pearl Inlay
Silicon Dioxide (SiO2) for Onyx; Aragonite (CaCO3) for Mother of Pearl
Bamboo Leaf Jasper
Silicified Siltstone or Jasper (SiO2)
Fossilized Dinosaur Bone
Permineralized Vertebrate Bone (mostly Calcium Phosphate replaced by Silica/Calcite)
Dinosaur Bone (Fossilized Bone)
Permineralized Dinosaur Bone (Bio-apatite replaced by quartz/silica)
Fossilized Dinosaur Bone
Permineralized Vertebrate Bone (Apatite/Quartz replacement)
Fossil Shark Tooth
Chondrichthyes (class); likely Lamniformes (order) fossilized in Apatite/Hydroxyapatite
Chert (Common Opal/Jasper mix)
Silicon Dioxide (SiO2) with impurities
Fossilized Shell
Invertebrate fossil (Bivalvia or Brachiopoda)
Chert Nodules (with Flint core)
Microcrystalline Quartz (SiO2)
Limestone
Calcium Carbonate (CaCO3)
Calcite
Calcium Carbonate (CaCO3)
Petrified Wood
Silicified wood (SiO2)
Petrified Wood
Petrified Wood (Silicified Wood)
Chert (Flint)
Silicon Dioxide (SiO2)
Banded Chert
Silicon Dioxide (SiO2)
Fossiliferous Limestone
Calcium Carbonate (CaCO3) with fossil inclusions
Chert Pebble
Cryptocrystalline Quartz (SiO2)
Fossil bivalve shell
Likely an extinct or modern-like ribbed cockle/scallop; exact genus requires locality and diagnostic hinge features
Mother of Pearl (Nacre) / Shell Fragment
Biogenic Calcium Carbonate (Aragonite and Conchiolin)
Chert (Flint)
Silicon Dioxide (SiO2)
Chert (and Fossilized Brachiopod shell)
Sedimentary Cryptocrystalline Quartz (SiO2)
Sedimentary Rock with Crafts (Pet Rock)
Sedimentary rock decorated with synthetic materials
Fossiliferous Limestone
Calcite (CaCO3) matrix with biogenic fragments
Petrified Wood
Silicified Wood (primarily Quartz / Chalcedony: SiO2)
Chert (likely flint), possibly chalcedony-rich
Microcrystalline quartz, SiO₂ (quartz/chalcedony)
Petrified Wood
Silicified Wood (SiO2)
Fossilized Coral
Rugosa or Tabulata coral fossil
Fossiliferous Limestone with Fossil Fragment
Fossiliferous Limestone (CaCO3 with organic remains)
Amber
Succinates (Organic compound: C10H16O)
Chert (River Pebble)
Microcrystalline Quartz (SiO2)
Pearl and Garnet Glass
Calcium Carbonate (CaCO3) for pearl; Silicon Dioxide (SiO2) for glass
Chert (Flint)
Silicon Dioxide (SiO2)
Travertine
Travertine (a terrestrial form of Limestone, CaCO3)
Brown Chert
Cryptocrystalline Quartz (SiO2)
Petrified Wood
Silicified wood (SiO2)
Fossilized Brachiopod
Brachiopoda (Phylum)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified wood / Permineralized wood (SiO2)
Mammoth or Mastodon Tooth Fossil
Mammuthus / Mammut tooth