Anthropogenic (Man Made Material Mimicking Sedimentary Rock)

Sandstone (Ferruginous)

Arenite (with high iron oxide content)

Siltstone with flute casts or scratch marks

Clastic Sedimentary Rock (Siltstone/Fine-grained Sandstone)

River Jasper (Chert/Chalcedony mix)

Silicon Dioxide (SiO2) with iron oxide and chlorite inclusions

Sandstone

Arenite (SiO2-rich)

Chert with Quartz Veining

Silicon Dioxide (SiO2)

Sandstone with Tafoni Weathering

Arenite (SiO2 based)

Red Sandstone

Clastic sedimentary rock (primarily Quartz and Feldspar with Iron Oxide cement)

Quartz (likely Rose Quartz or Milky Quartz based on color)

Quartz (SiO2 - Silicon Dioxide)

Limestone

Calcium Carbonate (CaCO3)

Conglomerate

Conglomerate (clastic sedimentary rock)

Sandstone

Arenite (Siliclastic sedimentary rock)

Jasper and Quartz conglomerate (River Rock)

Silicon Dioxide (SiO2) - Chalcedony and Quartz variety

Chert / Flint Nodule

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert

Chert (Microcrystalline Silica, SiO2)

Bumblebee Jasper

Calcite-bearing Volcanic Tuff containing Sulfur and Arsenic (Orpiment/Realgar)

Chert (Yellow/Tan)

Microcrystalline Quartz (SiO2)

Chert (variations include Flint or Jasper)

Silicon Dioxide (SiO2)

Coquina

Coquina (Bioclastic Calcarenite)

Jasper (Red/Yellow)

Silicon Dioxide (SiO2) with impurities

Ferruginous Sandstone (Ironstone)

Sedimentary rock with Limonite/Goethite cement

Chert (Yellow/Brown variety)

Chert (SiO2)

Limonite-stained Chert

Silicon Dioxide (SiO2) with Hydrated Iron Oxide (FeO(OH)·nH2O)

Ferruginous Sandstone (Ironstone)

Clastic sedimentary rock (SiO2 with Fe2O3/FeO(OH) cement)

Sandstone (Ferruginous)

Arenite (Fe-bearing Clastic Sedimentary Rock)

Chert (Nodular)

Microcrystalline Silica (SiO2)

Blue Lace Agate

Cryptocrystalline Quartz (SiO2) with trace minerals

Chert (and its variety Flint)

Silicon dioxide (SiO2) / Microcrystalline quartz

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Chert (often called Flint or Jasper)

Chert (Microcrystalline or Cryptocrystalline Silica, SiO2)

Conglomerate

Conglomerate (clastic sedimentary rock)

Red Sandstone

Arenite (high iron oxide content)

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Banded Gneiss

Gneiss (High-grade Metamorphic Rock)

Chert (Nodule)

Silicon Dioxide (SiO2)

Gneiss

Foliated Metamorphic Rock (Gneiss)

Sandstone

Clastic sedimentary rock (primarily Quartz and Feldspar)

Chert (Jasper/Agate variety)

Microcrystalline Quartz (SiO2)

Cockle Shell (Fossil or Recent)

Class Bivalvia, Family Cardiidae (e.g., Cerastoderma edule for common cockle)

Sandstone

Clastic Sedimentary Rock (composed mostly of SiO2)

Ferruginous Sandstone (Ironstone Conglomerate fragments)

Ferruginous clastic sedimentary rock (SiO2 cemented by Fe2O3)

Devil's Toenail

Gryphaea (extinct genus of foam oysters, typically composed of Calcite CaCO3)

Conglomerate

Conglomerate (clastic sedimentary rock)