Obsidian
Volcanic Glass (SiO2 + impurities)
Category
Browse anthropogenic (man made artifact) specimens identified by the Rock Identifier community.
Obsidian
Volcanic Glass (SiO2 + impurities)
Fossiliferous Limestone (with Crinoids/Coral)
Fossiliferous Limestone (CaCO3)
Banded Sandstone (Liesegang Rings)
Sedimentary sandstone with Iron oxide precipitates
Limestone
Calcareous sedimentary rock (primarily Calcium Carbonate, CaCO3)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
Ironstone (Limonitic Concretion)
Limonite (FeO(OH)·nH2O) with Goethite and Hematite inclusions
Fluorite with Rhodochrosite
Fluorite (CaF2) and Rhodochrosite (MnCO3)
Agate
Silicon Dioxide (SiO2)
Coral Fossil (Petrified Coral)
Scleractinia (Order) - Calcified Fossil Skeleton (CaCO3)
Greenstone
Greenschist (containing chlorite, epidote, and actinolite)
Kambaba Jasper (Crocodile Jasper)
Rhyolite containing Fossilized Cyanobacteria (Stromatolite)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Red Jasper (possibly Carnelian)
Silicon Dioxide (SiO2) with Hematite impurities
Milky Quartz
Silicon Dioxide (SiO2)
Limonite (Iron-rich Siltstone / Sandstone base)
Hydrous ferric oxide mixture (FeO(OH)·nH2O)
Limonite (Iron Ore)
Limonite (Hydrous iron(III) oxide-hydroxide mixture, primarily FeO(OH)·nH2O)
Jasper
Jasper (Silicon Dioxide, SiO2)
Quartzite
Quartzite (primarily SiO2)
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
Chalcedony Nodule (Carnelian/Agate)
Chalcedony (Silicon Dioxide, SiO2)
Sandstone (Calcareous or Ferruginous)
Clastic sedimentary rock (SiO2 with CaCO3 or Fe2O3 cement)
Serpentine
Serpentine-group (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4
Quartz
Silicon Dioxide (SiO2)
Sandstone (likely Quartz Sandstone)
Arenite (SiO2 based)
Basalt with Iron Oxidation
Amygdaloidal Basalt (silicate rock primarily plagioclase, pyroxene, and olivine)
Limestone
Calcium Carbonate (CaCO3)
Basalt (Polished River Stone)
Basalt (Extrusive Mafic Volcanic Rock)
Hematite
Hematite (Fe2O3)
Fluorite (Green)
Calcium Fluoride (CaF2)
Obsidian (Apache Tear)
Amorphous Volcanic Glass (SiO2 + impurities)
River Cobble (Quartzite)
Meta-orthoquartzite
Fluorite (Durango Fluorite)
Calcium Fluoride (CaF2)
Amygdaloidal Basalt
Amygdaloidal Basalt (Ca-rich Plagioclase, Pyroxene, and Olivine)
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
Agate
Silicon Dioxide (SiO2)
Gold Nugget
Native Gold (Au)
Chert with Asphaltum (or Tar)
Silica (SiO2) with natural Bitumen/Asphaltum
Agate (Polished Nodule)
Agate (Silicon Dioxide, SiO2)
White Agate (resembling Bone Chalcedony)
Cryptocrystalline Quartz (SiO2)
Quartzite Pebble
Quartzite (primarily SiO2)
Chert (Red Jasper)
Microcrystalline Quartz (SiO2)