Turritella Agate (Calligrapher Stone)
Silicified Elimia tenera (Chalcedony/Quartz)
sedimentary
Category
Sedimentary (Secondary Formation)
Browse sedimentary (secondary formation) specimens identified by the Rock Identifier community.
Yellow Ocherous Siltstone (Limonitic Shale)
Limonitic Siltstone / Goethite-rich Sedimentary Rock
sedimentary
Banded Chert
Microcrystalline Quartz (SiO2)
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Quartz Pebble
Silicon dioxide (SiO2)
sedimentary
Ammonite Fossil
Ammonoidea subclass (calcium carbonate / silica replacement)
fossil
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Green Opal
Hydrated amorphous silica (SiO2·nH2O)
mineraloid
Jasper
Silicon dioxide (SiO2)
Mineral
Microcrystalline Limestone
Limestone (CaCO3 with impurities)
sedimentary
Limestone Pebble
Calcium Carbonate (CaCO3)
sedimentary
Fossilized Dinosaur Skull (Tyrannosaurus rex)
Tyrannosaurus rex (permineralized fossil), rich in Hydroxylapatite/Silica
sedimentary
Chert (Jasper-like Silicate)
Microcrystalline Quartz (SiO2)
sedimentary
Pietersite
Brecciated Crocidolite in Quartz (Chalcedony)
metamorphic
Banded Calcite (often sold as Mexican Onyx)
Calcium Carbonate (CaCO3)
mineral
Sandstone (with secondary weathering/concretion)
Arenite (composed primarily of Quartz, SiO2)
sedimentary
Limonite (Iron Ore)
Limonite (Hydrous iron(III) oxide-hydroxide mixture, primarily FeO(OH)·nH2O)
mineral
Sandstone-based Concrete Fragment
Cementitious Composite with Sedimentary Aggregate
sedimentary (man-made/anthropogenic)
Pyritic Gneiss (with Garnet)
Gneiss containing Pyrite (FeS2) and Almandine Garnet (Fe3Al2(SiO4)3)
metamorphic
Chert (or potentially Jasper/Chalcedony)
SiO2 (Silicon Dioxide)
sedimentary
Red Jasper
Silicon Dioxide (Microcrystalline Quartz), SiO2
sedimentary
Limonite (Hydrated Iron Oxide / Bog Iron)
FeO(OH)·nH2O
Mineral (Sedimentary context)
Pink Stained Rock (Likely Quartzite or Sandstone with Iron Oxide Staining)
Quartzite (metamorphic) or Sandstone (sedimentary); coloration likely due to hematite or other iron oxides.
Metamorphic or Sedimentary (with staining)
Carnelian Agate
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
sedimentary
Fancy Jasper
Silicon Dioxide (SiO2) with iron and organic inclusions
sedimentary
Asphalt Concrete
Bituminous Concrete (Anthropic Rock)
sedimentary
Red Jasper
Silicon dioxide (SiO2) with Iron inclusions
sedimentary
Sandstone (Pebble)
Arenite (primarily SiO2)
sedimentary
Fossilized Bone (Petrified Bone)
Permineralized Bone Fossil
fossil
Red Jasper
Silicon Dioxide with Hematite inclusions (SiO2 + Fe2O3)
sedimentary
Beach Agate / Chalcedony Pebble
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Jasper with Quartz Veining
Silicon Dioxide (SiO2) with Hematite impurities
sedimentary
Limonitic Iron Ore / Goethite
Hydrated Iron(III) oxide-hydroxide (primarily FeO(OH)·nH2O)
sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Hematite impurities
sedimentary
Chert / Jasper / Agate (Chalcedony Group)
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified wood (primarily Silicon Dioxide, SiO2)
metamorphic
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Prehnite
Prehnite (Ca2Al2Si3O10(OH)2)
mineral
Limonite (Ironstone Concretion)
Limonite (FeO(OH)·nH2O)
sedimentary
Chert (Arrowhead Preform or Flake)
Microcrystalline Quartz (SiO2)
sedimentary
Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Quartz Geode with Chalcedony
Silicon Dioxide (SiO2) in Geode Form
sedimentary