Fossilized Bone Fragment
Permineralized Vertebrate Fossil (Hydroxyapatite replaced by Minerals)
Category
Browse mineral, often found as detrital grains in sedimentary rocks specimens identified by the Rock Identifier community.
Fossilized Bone Fragment
Permineralized Vertebrate Fossil (Hydroxyapatite replaced by Minerals)
Quartzite
Quartzite (primarily SiO2)
Porphyry (specifically Porphyritic Rhyolite or Andesite)
Porphyritic Igneous Rock (composed of Phenocrysts in an Aphanitic groundmass)
Blue Sapphire
Corundum (Al2O3) with iron and titanium impurities
White Sapphire
Corundum (Al2O3)
Granite
Granite (a common term for a felsic intrusive igneous rock)
Quartz (likely Clear Quartz or Rock Crystal)
Quartz (SiO2)
Chert (Flint variety)
Silicon Dioxide (SiO2)
Yellow Jasper (Chert)
Silicon Dioxide (SiO2) with iron inclusions
Siltstone or Mudstone
Argillaceous sedimentary rock
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Lepidolite (in Quartz Matrix)
Lepidolite [K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2]
Aquamarine
Beryl (Be3Al2Si6O18 with Fe2+ impurities)
Agate
Agate (Microcrystalline Quartz, SiO2)
Quartzite
Quartzite (SiO2)
Kyanite
Kyanite (Al2SiO5)
Carnelian
Carnelian (Silicon Dioxide: SiO2)
Pink Opal / Peruvian Opal
Hydrated amorphous silicon dioxide (SiO2·nH2O)
Ruby
Corundum (Al2O3 with Chromium impurities)
Limestone
Calcium Carbonate (CaCO3)
Pegmatitic Granite
Granite (Alkali-feldspar granite) with Quartz and Orthoclase
Jasper
Chalcedony (cryptocrystalline quartz), SiO2
Ironstone Concretion (Moqui Marble type)
Iron oxide concretion (Goethite/Hematite and Sandstone)
Quartzite / Sandstone / Chert Mix
Silicon Dioxide (SiO2)
Quartzite
Quartzite (SiO2)
Fossiliferous Limestone
Calcium Carbonate - CaCO3
Garnetiferous Quartzite (Garnet Gneiss Pebble)
Garnet-bearing Quartzite or Quartz-Feldspar Gneiss
Quartzite
Quartzite (SiO2)
Red Jasper
Silicon Dioxide (SiO2) with Iron inclusions
Chalcopyrite
Chalcopyrite (CuFeS2)
Quartzite
Quartzite (primarily SiO2)
Black Tourmaline
Schorl (Na(Fe2+)_{3}Al_{6} (BO_{3})_{3} (Si_{6}O_{18})(OH)_{4})
Diopside (likely Chromian Diopside)
Diopside, part of Clinopyroxene family of inosilicates. Chemical formula: CaMgSi2O6. The green variety is often Chromian Diopside due to chromium impurities.
Quartzite
Quartzite (SiO2)
Granite
Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)
Petrified Wood
Silicified Wood (SiO2 permineralization)
Blue Quartzite (Aventurine)
Silicon Dioxide (SiO2) with mineral inclusions
River Stone (River Pebbles)
Alluvial Deposit (typically Quartzite, Sandstone, or Granite clasts)
Jasper with Agate and Quartz Inclusions
Silicon Dioxide (SiO2) - Chalcedony / Quartz aggregate
Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Almandine Garnet
Almandine (Fe3Al2(SiO4)3)
Howlite
Howlite (Calcium borosilicate hydroxide, Ca2B5SiO9(OH)5)