Anthropogenic (Man Made Material Mimicking Sedimentary Rock)

Sandstone

Arenite (Clastic Sedimentary Rock)

Siltstone

Siltstone (siliciclastic sedimentary rock)

Piddock bored rock (likely Mudstone or Shale)

Ichnofossil (Gastrochaenolites borings) in Fine-grained Sedimentary Rock

Yellow Jasper

Jasper, a microcrystalline variety of Quartz (SiO2) with iron inclusions

Sandstone (Banded)

Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide staining)

Red jasper (iron-rich chalcedony), possibly brecciated

Jasper: microcrystalline quartz, SiO₂, colored mainly by iron oxides/hydroxides

Quartzite River Rock

Quartzite (primarily SiO2)

Chert

Microcrystalline Quartz (SiO2)

Chert (Common Opal/Chalcedony mixture)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Sandstone (primarily SiO2 with iron oxide cement Fe2O3)

Glacial Erratic (Sandstone/Quartzite)

Glacial Erratic specimen (likely Orthoquartzite or Feldspathic Sandstone)

Fossil Coral in Limestone

Scleractinia (Anthomastodon or similar) in Sedimentary Calcarenite

Sandstone with Iron Staining

Arenite (SiO2 with Fe2O3)

Jasper

Silicon dioxide (SiO2)

Weathered quartz-rich rock fragment

Likely quartz-bearing sandstone or granitic rock; exact identification is uncertain from the image

Chert (Jasper/Chalcedony)

Microcrystalline Quartz (SiO2)

Rounded quartz-rich pebble

Likely microcrystalline quartz (SiO₂), possibly milky quartz or a pale quartzite fragment

Granite Gneiss

Gneiss (High-grade Metamorphic Rock)

Weathered basalt or iron-rich volcanic rock

Mafic volcanic rock, likely basalt; exact identification requires testing

Sandstone

Arenite

Sandstone

Sandstone (Arenite)

Red Sandstone

Arenite (Ferruginous Sandstone)

Quartz Pebble

Silicon Dioxide (SiO2)

Fossiliferous Limestone with Crinoid Stem fragment

Calcite (CaCO3) containing Crinoidea fossils

Quartz Vein in Hematitic Siltstone

Hydrothermal Quartz (SiO2) in Ferriferous Matrix

Gravel/Common Siltstone

Siltstone (fine-grained siliciclastic sedimentary rock)

Sandstone

Sandstone (SiO2 dominated clastic sedimentary rock)

Chert / Flint

Microcrystalline or cryptocrystalline quartz (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (composed primarily of SiO2 with Fe2O3 cement)

Gravelly, weathered sediment (likely glacial till)

Unconsolidated diamicton; mixed lithologies, commonly including quartz, feldspar, and weathered silicate rock fragments

Sandstone / Limestone

Sedimentary Rock (Quartz Sandstone or Calcareous Grainstone)

Possible flint or slag fragment

Microcrystalline quartz (chalcedony), or iron-rich industrial slag

Weathered mica-rich metamorphic rock

Probable biotite schist or mica schist

Sandstone (Red)

Arenite (primarily SiO2 with Fe2O3)

Red Sandstone

Arenite (composed primarily of Quartz and Iron Oxide)

Mosasaur Tooth Fossil

Mosasaurus sp.

Chert (with Chalky Cortex)

Silicon Dioxide (SiO2)

Sandstone (Quartzose Sandstone)

Arenite (SiO2 principal component)

Banded gneiss pebble

Gneiss, typically quartz–feldspar–mica assemblage

Sandstone

Arenite (SiO2 based)

Sandstone (Quartzose)

Arenite