Anthropogenic (Man Made Material Mimicking Sedimentary Rock)

Green Aventurine

Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)

Chert (flint), brown variety

Microcrystalline quartz (SiO₂)

Man-made Jewelry (Metal and Glass/Plastic)

Synthetic Alloy and Amorphous Solid (SiO2/Polymer)

Sandstone

Arenite (composed primarily of SiO2)

Sandstone

Arenite

Chert (Flint / Jasper)

Silicon Dioxide (SiO2)

Man-made Ceramic / Clay Figurine

Aluminosilicate Ceramic (Processed Clay)

Tumbled opalite (likely man-made glass)

Opalite glass; a synthetic opalescent glass, not a natural mineral species

Chert (Arrowheads)

Microcrystalline Quartz (SiO2)

Red Sandstone

Quartz Arenite (iron-stained) / SiO2

Banded Chert (River Stone)

Silicon Dioxide (SiO2)

Bituminous Coal (with Anthracite or Vitrinite inclusion)

Organic-rich Sedimentary Rock (Carboniferous classification)

Banded Sandstone

Arenite with Liesegang banding

Paving-concrete aggregate with a rounded stone

Polymictic gravel aggregate; the central clast appears to be weathered sandstone or volcanic rock

Dalmatian jasper

Porphyritic microcrystalline quartz-rich rock, commonly sold as Dalmatian jasper; spots are chiefly arfvedsonite/amphibole minerals, sometimes altered feldspar

Red-orange cabochon, likely carnelian or glass imitation

Carnelian: chalcedony (microcrystalline SiO₂), commonly iron-colored

Sandstone (Pebble)

Sandstone (arenite, arkose, wacke depending on composition)

Chert (likely flint)

Microcrystalline quartz, SiO₂

Carved Mottled Greenish-Yellow Crystal/Glass Object

Unknown; possibly a form of quartz (chalcedony/jadeite/nephrite) or glass/resin.

Conglomeratic concrete or asphalt aggregate surface with dark bituminous chunks

Polymictic gravel aggregate; dark pieces likely bitumen/asphalt, not a natural rock

Sandstone

Arenite (SiO2 primarily)

Blue glass-like bead or gemstone keychain ornament

Indeterminate; likely cobalt-blue glass or synthetic blue spinel, not identifiable as a natural mineral from the image

Sandstone (with iron staining)

Quartz Arenite / Ferruginous Sandstone

Chert (Black Flint)

Silicon Dioxide (SiO2)

Sandstone (likely Quartzose Sandstone)

Arenite

Iron-stained quartz-rich rock, possibly jasper or chert

Microcrystalline quartz (SiO₂) with iron oxides/hydroxides

Coral Rock (Coquina)

Biogenic Limestone (Calcium Carbonate - CaCO3)

Sandstone (Red/Brown Variety)

Arenite (composed primarily of SiO2 with Fe2O3 iron oxide inclusions)

White Marble

Recrystallized Calcite Rock (CaCO3)

Porous iron-rich rock or slag-like material

Unidentified; possibly limonite/goethite-rich ironstone

River Pebbles (Chert and Quartzite)

Sedimentary Clastic Rock (Silica-rich)

Chert (Arrowhead/Projectile Point)

Cryptocrystalline Quartz (SiO2)

Coquina / Fossiliferous Limestone

Calcareous bioclastic sedimentary rock (CaCO3)

Opalite (likely man-made glass)

Opalite; amorphous silica glass, not a natural mineral

Small rounded pebble (rock type indeterminate)

Unidentified fine-grained lithic pebble

Hematite

Iron(III) oxide (Fe2O3)

Banded Calcite (often sold as 'Mexican Onyx' or 'Green Onyx')

Calcite (Calcium Carbonate, CaCO3)

Sandstone (specifically Arkose or Quartz Arenite)

Arenite (primarily SiO2 with possible Feldspar)

Chert (likely flint)

Microcrystalline quartz (SiO₂), variety chert; flint is a dark chert variety

Slate

Metamorphic Pelitic Rock

Flint (chert) fragment

Microcrystalline quartz (SiO₂), commonly called flint when dark

Pink Granite

Phaneritic Felsic Igneous Rock (Granite)