Tufa (Calcareous Tufa)
Calcareous Tufa (Precipitated CaCO3)
Category
Browse organic mineraloid and mineral specimens identified by the Rock Identifier community.
Tufa (Calcareous Tufa)
Calcareous Tufa (Precipitated CaCO3)
Chert (often called Flint)
Chert (Microcrystalline Quartz, SiO2)
Botryoidal Chalcedony
Cryptocrystalline Silicon Dioxide (SiO2)
Sodalite (Dotted or Spotted Variety)
Sodalite (Na8(Al6Si6O24)Cl2)
Kyanite (Purple variety)
Kyanite (Al₂SiO₅)
Clear Quartz (Rock Crystal Fragments)
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Picture Jasper
Silicon Dioxide (SiO2) with iron oxide and organic impurities
Chert (specifically Flint or Common Chert)
Chert (Cryptocrystalline Silica, SiO2)
Ironstone Concretion (Limonite/Goethite)
Iron oxide concretion (contains FeO(OH)·nH2O)
Dragon Stone (Septarian Nodule/Concretion)
Septarian Concretion (Composition: Calcite, Aragonite, Limestone/Clay)
Ammonite Fossil
Ammonoidea (subclass)
Picture Jasper
Tectonically broken chalcedony (SiO2)
Asphalt (Bituminous Concrete)
Composite material (bitumen binder with mineral aggregate)
Brachiopod Fossil in Limestone
Phylum Brachiopoda (likely Order Spiriferida), CaCO3 (Calcite)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified wood (Quartz/Chalcedony/SiO2)
Jasper
Agate/Jasper (Microcrystalline Quartz, SiO2)
Septarian Nodule (Dragon Stone)
Septarian Concretion (CaCO3 with Siderite and Calcite)
Petrified Wood
Silicified Wood (SiO2)
Septarian Nodule (Dragon Stone)
Septarian Geode (CaCO3 + Mg + Fe)
Petrified Wood
Silicified Wood (SiO2)
Opalite
Synthetic Opalized Glass
Septarian Nodule
Septarian Concretion (CaCO3 with Siderite/Calcite/Aragonite)
Jasper
Jasper (Silicon Dioxide, SiO2)
Banded Chert
Microcrystalline Quartz (SiO2)
Chert (Chalcedony/Agate)
Microcrystalline Quartz (SiO2)
Ironstone Concretion / Hematite Nodules
Ferruginous Sedimentary Rock (primarily Hematite Fe2O3 and Goethite FeO(OH))
Petrified Wood
Silicified Wood (primarily SiO2)
Coral Fossil (Petrified Coral)
Scleractinia (Order) - Calcified Fossil Skeleton (CaCO3)
Travertine (often colloquially called Tufa)
Chemical Sedimentary Calcium Carbonate (CaCO3)
Petrified Wood
Silicified Wood (primarily Quartz / Chalcedony: SiO2)
Chert (Jasper)
Sedimentary Cryptocrystalline Quartz (SiO2)
Blue Agate (Dyed Chalcedony)
Silicon Dioxide (SiO2)
Chert (Nodule)
Silicon Dioxide (SiO2)
Sandstone
Arenite (clastic sedimentary rock)
Fossil Sand Dollar (Echinoidea)
Phylum Echinodermata, Class Echinoidea (likely Dendraster or Scutella)
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Chert (Yellow Jasper/Flint)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Chert (often called Flint in this context)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Fossilized Wood (with Coal and Limonite)
Petrified Wood (Silicified or Carbonized Flora)
Chert (Jasper variety)
Silicon Dioxide (SiO2)