Ironstone Nodules in Chalk/Limestone
Limonite/Goethite concretions (FeO(OH)·nH2O) in Calcium Carbonate matrix (CaCO3)
Category
Browse organic materia (not a rock or mineral) specimens identified by the Rock Identifier community.
Ironstone Nodules in Chalk/Limestone
Limonite/Goethite concretions (FeO(OH)·nH2O) in Calcium Carbonate matrix (CaCO3)
Chert (Flint)
Chert (Cryptocrystalline Silica, SiO2)
Chert (often called Flint in dark varieties)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Jasper variety)
Silicon Dioxide (SiO2)
Graphite
Graphite (Carbon, C)
Chert (Field Stone)
Microcrystalline Quartz (SiO2)
Dalmatian jasper (often sold as Dalmatian stone)
Quartz-bearing leucocratic alkali-feldspar–aegirine/arfvedsonite porphyritic rock; commercial “jasper” designation
Pyrite Concretion
Iron Sulfide (FeS2) in Sedimentary Matrix
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Chert (Jasper)
Microcrystalline Quartz (SiO2) with hematite impurities
Amber
Fossilized Tree Resin
Chert (River Stone)
Microcrystalline Quartz (SiO2)
Black Pearl (Tahitian Pearl)
Aragonite / Calcite (CaCO3) with Conchiolin
Fossiliferous Limestone
Calcite-rich Sedimentary Rock (CaCO3)
Jasper
Jasper (Cryptocrystalline variety of Quartz, SiO2)
Quartzite
Quartzite (primarily SiO2)
Petrified Wood
Silicified Wood (primarily Quartz / Chalcedony: SiO2)
Limestone
Calcium Carbonate (CaCO3)
Chert (Polished/Worn)
Microcrystalline quartz (SiO2)
Chert (Flint Nodules)
Silicon Dioxide (SiO2)
Chert (White Chert or Flint)
Microcrystalline Quartz (SiO2)
Limestone with Lichen
Carbonate Sedimentary Rock (primarily CaCO3)
Chert / Flint
Chert (Cryptocrystalline Silica, SiO2)
Amber
Succinite (Organic Mineraloid)
Limestone
Sedimentary rock composed mainly of calcite (CaCO3)
Shark Tooth Fossil
Carcharocles megalodon or similar extinct shark tooth
Fossilized Gastropod / Coral
Phylum Mollusca / Cnidaria (Silicified or Calcified)
Banded Chert
Chert (Silicon Dioxide, SiO2)
Chert (Limestone/Flint variant)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Chert (specifically Jasper/Brown Chert)
Silicon Dioxide (SiO2)
Fossiliferous Limestone (Coquina)
Biogenic Limestone (Calcium Carbonate, CaCO3)
Black Jasper (Black Onyx substitute)
Silicon Dioxide (SiO2) with carbonaceous impurities
Chert (Basanite / Jasperoid)
Microcrystalline Quartz (SiO2)
Coal
Bituminous coal (Complex organic sedimentary rock)
Bituminous Coal
Organic-rich sedimentary rock (Complex hydrocarbons)
Hag Stone
Perforated Sedimentary Rock (typically Flint or Limestone)
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (and/or Flint)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Amber
Organic gemstone (Succinite)
Amber
Succinates (Organic Gemstone)
Chert Cobble / Quartzite River Stone
Microcrystalline Quartz (SiO2) / Quartzite
Fossiliferous Limestone with Fossil Fragment
Fossiliferous Limestone (CaCO3 with organic remains)