Anthracite Coal
Anthracite (Carbon-based organic sedimentary rock transitioned to metamorphic)
Category
Browse sedimentary (fossilized organic remain) specimens identified by the Rock Identifier community.
Anthracite Coal
Anthracite (Carbon-based organic sedimentary rock transitioned to metamorphic)
Precious Coral
Corallium rubrum (Calcium carbonate with trace carotene)
Septarian Nodule (Dragon Stone)
Septarian Nodule (Calcium Carbonate/Aragonite/Calcite Concretion)
Kidney Stone
Calcium Oxalate (CaC2O4), Uric Acid, or Struvite
Shale or Argillite
Shale (sedimentary) / Argillite (metamorphic)
Graphite
Graphite (C)
Pyrite
Pyrite (Iron Disulfide), FeS2
Chert / Flint
Chert (varieties include Flint)
Coal (specifically Bituminous or Anthracite)
Organic sedimentary rock; primarily Carbon (C) with varying H, S, O, N
Banded Chert
Chert (a microcrystalline variety of quartz, SiO2 with minor impurities)
Druzy Chalcedony/Quartz on Fluorite core
Silicon Dioxide (SiO2) on Calcium Fluoride (CaF2)
Shale or Argillite
Shale (fine-grained clastic sedimentary rock) or Argillite (low-grade metamorphic rock derived from shale)
Tiger's Eye
Silicon dioxide (SiO2) with fibrous inclusions of crocidolite (riebeckite)
Graphite-veined Quartzite
Meta-sedimentary Quartzite with Carbonaceous/Graphitic Inclusions (SiO2 + C)
Petrified Wood
Silicified Wood (primarily SiO₂ - Silicon Dioxide)
Porphyritic Basalt or Diabase with Plagioclase Phenocrysts
Porphyritic Basalt or Diabase; Mineral: Plagioclase Feldspar
Pearl (incorporated into jewelry)
Aragonite and Calcite (CaCO3)
Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3 with Carotenoid pigments)
Pearl
Calcium Carbonate (CaCO3) + Conchiolin
Potassium-Rich Silicate Clay (inferred from biological context)
Phyllosilicate group (likely Illite or Smectite within surrounding soil substrate)
Grass (Organic Matter/Soil)
Poaceae (family of monocotyledonous flowering plants)
Chert (varietal: Jasper or Flint likely, but definitive identification is difficult from image)
SiO₂ (silicon dioxide)
Graphite
Graphite (Carbon, C)
Pink Opal / Peruvian Opal
Hydrated amorphous silicon dioxide (SiO2·nH2O)
Precious Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
Turquoise and Red Coral
CuAl6(PO4)4(OH)8·4H2O (Turquoise) and Corallium rubrum (Red Coral)
Pink Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
Paper (Cellulose)
Cellulose (C6H10O5)n
Pearl
Calcium carbonate (CaCO3) in the form of Aragonite or Calcite
Pearl
Calcium Carbonate (CaCO3) - Aragonite/Calcite
Red Jasper (beads)
SiO₂ (Silicon Dioxide)
Turquoise and Red Coral (with Grizzly Bear Claw)
Turquoise (CuAl6(PO4)4(OH)8·4H2O) and Precious Coral (Corallium rubrum)
Pyrite
Pyrite (FeS2)
Chert / Flint
Chert (varietal name for microcrystalline quartz). Chemical formula: SiO₂
Oak-grain Laminate (Industrial/Decorative Furniture Finish)
Melamine Resin-impregnated Decorative Paper on Particleboard (Cellulose/Thermosetting Plastic)
Onyx (Black) and Mother of Pearl Inlay
Silicon Dioxide (SiO2) for Onyx; Aragonite (CaCO3) for Mother of Pearl
Pyrite
Pyrite (Iron Disulfide), FeS2
Moss Agate
Chalcedony (SiO2) with inclusions of manganese or iron oxides
Stardust (Micrometeorite)
Chondrite / Micrometeorite (Extraterrestrial Silicate)
Moss Agate
Chalcedony (SiO2) with inclusions of hornblende or chlorite
Red Coral
Corallium rubrum
Natural Pearl (appearing in a jewelry setting)
Calcium Carbonate (mostly Aragonite), CaCO3 with Conchiolin