Rock (Likely Sedimentary)

Tumbled river pebble, likely limestone or weathered chert

Indeterminate carbonate/siliceous pebble; possible micritic limestone or chert

Chert (Nodule)

Microcrystalline or Cryptocrystalline Silica (SiO2)

Fossil plant impression slab

Fossilized plant compression/impression; exact taxon indeterminate from the image

Weathered Sandstone Cobble

Arenite / Quartz Sandstone

Fossilized Shell in Limestone

Carbonate sedimentary rock with Bivalvia or Brachiopoda remains

Banded chert or siliceous sedimentary rock

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide staining and possible carbonate/clay layers

Likely sandstone

Quartz-rich sandstone, probably arkosic or lithic sandstone

Sandstone

Arenite (Siliclastic sedimentary rock)

Fossiliferous Shale

Sedimentary Clastic Rock with fossil inclusions (likely Brachiopod or Bivalve impressions)

Sandstone Pebble

Arenite (SiO2 based)

Chert (Brecciated Chert)

Silicon Dioxide (SiO2)

Quartz fragment

Quartz (silicon dioxide, SiO₂)

Sandstone (likely Greywacke or Lithic Sandstone)

Arenite / Wacke

Sandstone (likely Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Sandstone (likely Siltstone)

Arenite or Siltstone (high SiO2 content)

Chert Arrowhead (Lithic Artifact)

Chert (Cryptocrystalline Quartz, SiO2)

Sandstone (River Pebble)

Clastic Sedimentary Rock (primarily Quartz)

Fossiliferous Limestone

Autochthonous Biogenic Sedimentary Rock (CaCO3)

Weathered limestone or calcareous sandstone

Calcitic carbonate rock, likely limestone (CaCO₃), possibly slightly dolomitic

Chert (Jasper/Agate mix)

Microcrystalline Quartz (SiO2)

Sandstone (with Chert/Quartzite)

Arenite (SiO2 primarily)

Limestone

Calcite-rich carbonate rock (primarily CaCO₃)

Limestone (specifically Travertine or Tufa)

Calcium Carbonate (CaCO3)

Likely quartz-rich sedimentary pebbles

Quartz arenite or chert-like siliceous rock; exact identification is uncertain from the photograph

Likely bituminous coal

Coal, predominantly carbon-rich organic matter; exact rank cannot be confirmed visually

Sandstone

Arenite (SiO2 primarily)

Quartz-veined Mudstone or Argillite

SiO2 (Quartz) in Siltstone/Mudstone matrix

Pebble (likely Siltstone or fine-grained Sandstone)

Sedimentary Clastic Rock

Mixed tumbled river pebbles and beach stones

Polymictic alluvial gravel; components include quartz, chert, jasper, sandstone, and altered volcanic rocks

Banded metamorphic rock, likely gneiss

Banded quartzofeldspathic gneiss (probable paragneiss or orthogneiss)

Probable mica schist

Schist, likely muscovite–biotite schist

Blue Chalcedony (likely dyed Agate)

Silicon Dioxide (SiO₂)

Sandstone (Calcareous Sandstone)

Calcareous Sandstone (primarily SiO2 with CaCO3 cement)

Rounded river pebble, likely altered limestone or sandstone

Probable micritic limestone (calcite-rich, CaCO₃) or fine-grained sandstone

Small rounded pebble, likely sandstone or weathered limestone

Indeterminate clastic carbonate/siliciclastic pebble; mineral composition appears dominated by quartz, feldspar, and/or calcite

Small shell fragment (likely gastropod or bivalve fossil)

Fossilized calcium-carbonate shell; chiefly aragonite or calcite (CaCO₃)

Banded Sedimentary Rock (Wishbone Stone / Banded Quartzite or Limestone)

Silicified limestone or banded sedimentary rock with mineral veins

Small weathered mineral/rock fragment

Indeterminate; possibly quartz-bearing feldspathic rock or calcite-rich specimen

Fossiliferous Sandstone (with Brachiopod or Bivalve mold)

Clastic Sedimentary Rock with Macrofossil Mold

Quartz (Chert/Chalcedony variety)

Silicon Dioxide (SiO2)

Blue-gray stone fragment, possibly slate or fine-grained basalt

Undetermined; appearance is consistent with slate (fine-grained metamorphosed mudstone), but the image is insufficient for reliable identification.

Sedimentary Pebble (Sandstone)

Clastic Sedimentary Rock (SiO2 dominant)