Sedimentary (Anthropogenic)

Limestone

Calcium Carbonate (CaCO3)

Limestone

Calcite (CaCO3)

Sandstone or possibly a conglomerate

Arenite (if sandstone)

Polished red jasper and carnelian-like stones

Jasper: microcrystalline quartz (SiO₂), commonly colored by iron oxides; translucent piece may be carnelian, a chalcedony variety

Ocean Jasper

Orbicular Jasper (Silicon Dioxide, SiO2)

Red Jasper

Silicon Dioxide (SiO2) with Hematite (Fe2O3) inclusions

Smooth gray river pebble

Likely fine-grained sandstone or siltstone; exact identification requires a fresh surface and tests

Honey calcite (orange calcite)

Calcite, calcium carbonate (CaCO₃)

Quartz Geode with Calcite

Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3)

Red Jasper

Silicon Dioxide (SiO2) with Hematite (Fe2O3)

Red Jasper

Red Jasper (SiO2)

Quartz on Host Rock

Silicon Dioxide (SiO2)

Jasper with Iron Staining

Silicon Dioxide (SiO2) with Hematite (Fe2O3)

Quartz Geode

Silicon Dioxide (SiO2)

Bivalve Fossil in Sedimentary Matrix

Fossiliferous Mudstone (Class: Bivalvia)

Sandstone

Sedimentary Clastic Rock (Quartz-rich)

Quartzite Conglomerate

Conglomerate (SiO2 rich)

Sandstone or similar clastic rock

Arenite

Jasper with Hematite Inclusions

Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3)

Limonite (Ironstone Concretion)

Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)

Sandstone (likely Graywacke or Lithic Arenite)

Clastic sedimentary rock predominantly composed of silicate grains

Polished black stone, likely hematite or black jasper

Hematite (Fe₂O₃) or opaque chalcedony/jasper (SiO₂); image-only identification is uncertain

Sandstone (Tumbled / Rounded)

Sedimentary Rock (Quartz arenite)

Limestone

Calcareous sedimentary rock (CaCO3)

Ferruginous Siltstone

Siltstone with Magnetite/Hematite bands

Likely weathered sandstone fragment

Sandstone, composed mainly of quartz (SiO₂) and feldspar grains in a clay, silica, or iron-oxide cement

Tumbled brown stone, possibly jasper or weathered chert

Uncertain; likely microcrystalline quartz (SiO₂), potentially iron-stained jasper/chert

Weathered sandstone

Quartz-rich sandstone, locally iron-oxide stained (SiO₂-dominant)

Chert / Quartz Pebble

Silicon Dioxide (SiO2)

Banded sandstone

Quartz-rich sandstone (quartz arenite or feldspathic sandstone; exact type cannot be determined from the image)

Likely bituminous coal

Coal, predominantly carbon-rich organic matter; exact rank cannot be confirmed from the image

Sandstone or Siltstone

Arenite or Siltstone

Fossilized Fish Skeleton in Matrix

Vertebrata (Class: Actinopterygii), typically found in limestone or shale matrices

Sandstone Pebble

Quartzose Sandstone (Sedimentary Rock)

Sandstone Pebble

Sedimentary Rock (Quartzose Sandstone)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Banded gneiss

Gneiss, chiefly quartz–feldspar–mica

Banded Iron Formation

Banded Iron Formation (BIF)

Glauconitic Sandstone

Glauconitic sandstone ((K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)

Chert (Sedimentary Rock)

Silicon Dioxide (SiO2)

Jasper

Silicon dioxide (SiO2)

Quartz

Silicon dioxide (SiO2)