Limestone (Concretionary or Tufa)
Calcium Carbonate (CaCO3)
sedimentary
Category
Organic (Geological Relative)
Browse organic (geological relative) specimens identified by the Rock Identifier community.
Petrified Wood
Silicified Wood (SiO2)
Mineral / Fossil
Shale
Shale (fine-grained clastic sedimentary rock)
Sedimentary
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Chert (Septarian or Nodular variety)
Microcrystalline Quartz (SiO2)
sedimentary
Moss Agate
Cryptocrystalline Quartz (SiO2 with Manganese or Iron Oxide inclusions)
mineral
Moqui Marble (Shaman Stone)
Iron Oxide Concretion (composed primarily of Quartz sand with Hematite/Goethite shell)
sedimentary
Apatite
Apatite Group (e.g., Fluorapatite Ca5(PO4)3F, Chlorapatite Ca5(PO4)3Cl, Hydroxylapatite Ca5(PO4)3(OH))
mineral
Petrified Wood
Silicified Wood (SiO2 - primarily Quartz/Chalcedony/Opal)
Mineral/Fossil (Sedimentary context)
Red Jasper
Silicon dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Yellow Chert
Sedimentary cryptocrystalline quartz (SiO2)
sedimentary
Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Green Jasper (with Quartz veining)
Jasper (Silica-rich microcrystalline variety of Quartz), formula: SiO2
sedimentary
Banded Chert
Microcrystalline Quartz (SiO2)
sedimentary
Ironstone Concretion (Iron-rich Mudstone)
Siderite / Geothite concretion (FeCO3 / FeO(OH))
sedimentary
Amber
Succinite (Carbon-based organic compound; approximate formula C10H16O)
Mineraloid
Chert (Jasper variation)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Limestone (Weathered)
Calcium Carbonate (CaCO3)
sedimentary
Petrified Wood
Silicified Wood (primarily Quartz / Chalcedony: SiO2)
metamorphic
Quartz Geode in Chert/Limestone Matrix
Silicon Dioxide (SiO2) within Sedimentary Host Rock
sedimentary
Chert (River Pebble)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (and Jasper variety)
Microcrystalline Quartz (SiO2)
sedimentary
Anthracite Coal
Anthracite (a variety of coal, predominantly carbon)
Sedimentary Rock (Metamorphosed)
Travertine
Calcareous Tufa (CaCO3)
sedimentary
Travertine (Tufa)
Calcium Carbonate (CaCO3)
sedimentary
Petrified Wood
Silicified wood (Quartz/Chalcedony - SiO2)
sedimentary
Sodalite
Sodalite (Na4Al3Si3O12Cl)
Mineral
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide / Chalcedony)
metamorphic
Septarian Nodule (Dragon Stone)
Septarian Nodule (Calcium Carbonate/Aragonite/Calcite Concretion)
sedimentary
Jasper
Agate/Jasper (Microcrystalline Quartz, SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Chert (Iron-stained River Cobble)
Microcrystalline Quartz (SiO2)
sedimentary
Quartz with Iron Stains
Quartz (SiO2) with iron oxide/hydroxide staining
Mineral
Fossiliferous Limestone
Calcite-rich Sedimentary Rock (CaCO3)
sedimentary
Septarian Nodule
Septarian Concretion (CaCO3 with Siderite/Calcite/Aragonite)
sedimentary
Water and Silt (Sedimentary Environment)
Suspended Sediment / H2O (dihydrogen monoxide)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
mineral
Seraphinite
Clinochlore (a variety of the chlorite group)
mineral
Fancy Jasper (Agate/Chert mix)
Silicon Dioxide (SiO2) with impurities
sedimentary