Rock (Likely Sedimentary)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Weathered rock fragment (likely limestone)

Calcite-rich limestone, composition and identity uncertain from the image

Porphyritic granite (likely orbicular/porphyritic granitoid)

Quartz–feldspar granitoid; commonly composed of K-feldspar, plagioclase, quartz, and biotite/hornblende

Banded sandstone pebble

Quartz-rich sandstone, likely arkosic or ferruginous sandstone

Likely weathered river pebble

Unidentified rounded lithic pebble; the image does not show enough detail to determine its rock species

Biotite-rich schist (probable)

Mica schist, rich in biotite (K(Mg,Fe)₃AlSi₃O₁₀(OH,F)₂); exact identification is uncertain from the image alone.

Sandstone

Arenite (primarily Quartz-rich)

Sandstone

Arenite (Siliclastic sedimentary rock)

Rounded pebble with a brown mineral or rock inclusion

Unidentified lithic pebble; the pale matrix and brown patch cannot be identified reliably from the image

Small weathered rock fragments

Unidentified lithic fragments; composition cannot be determined from the image

Chert (Nodule)

Microcrystalline or Cryptocrystalline Silica (SiO2)

Concretion-bearing sedimentary rock

Likely a carbonate-rich concretion in mudstone or siltstone; exact composition cannot be confirmed visually

Rounded brown pebble, likely quartz-rich river stone

Indeterminate lithic pebble; possibly iron-stained quartzite or chert

Sandstone (River Pebble)

Clastic Sedimentary Rock (primarily Quartz)

Fossiliferous Limestone

Autochthonous Biogenic Sedimentary Rock (CaCO3)

Quartz-rich rock fragment

Unidentified quartz–feldspar-rich rock; exact lithology cannot be determined from the image

Likely mica-rich schist fragment

Mica schist; exact mineral identification is uncertain from the image

Fine-grained sedimentary rock (likely sandstone)

Quartz-rich sandstone; exact identification is uncertain from the image

Banded chert or siliceous sedimentary rock

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

Sandstone (likely Siltstone)

Arenite or Siltstone (high SiO2 content)

Likely sandstone

Quartz-rich sandstone, probably arkosic or lithic sandstone

Large bivalve shell fossil (possibly a clam)

Fossilized bivalve; exact taxon cannot be determined from the image

Fossilized Shell in Limestone

Carbonate sedimentary rock with Bivalvia or Brachiopoda remains

Sandstone (likely Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Weathered granite or granitic gneiss block

Granite, chiefly quartz, feldspar, and mica; possibly gneiss if the visible banding is structural

Mica-bearing metamorphic rock with a dark mica crystal

Likely schist or mica-rich gneiss; dark crystal appears to be biotite, though identification from the photo is uncertain

Limestone

Calcite-rich carbonate rock (primarily CaCO₃)

Fossil plant impression slab

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

Weathered basalt or volcanic breccia

Fine-grained mafic volcanic rock, likely basalt (plagioclase–pyroxene ± olivine), possibly brecciated

Small weathered mineral/rock fragment

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

Chert (Brecciated Chert)

Silicon Dioxide (SiO2)

Drill-core rock, likely foliated metamorphic rock

Indeterminate from the photograph; possibly slate, phyllite, or schist

Likely biotite-rich schist or gneiss

Mica schist (quartz–feldspar–biotite assemblage; exact identification requires examination)

Rounded river stone (likely iron-stained sandstone or siltstone)

Indeterminate ferruginous sandstone/siltstone; composition cannot be confirmed from the image

Tumbled cream-colored stone, possibly quartz or calcite

Indeterminate from photograph; likely microcrystalline quartz (SiO₂) or calcite (CaCO₃)

Tumbled river pebble, likely limestone or weathered chert

Indeterminate carbonate/siliceous pebble; possible micritic limestone or chert

Iron-stained river pebble (likely jasper or chert)

Silica-rich microcrystalline quartz, SiO₂, colored by iron oxides; exact identification is uncertain from the image

Banded gneiss

Gneiss, likely quartz–feldspar–mica gneiss

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

Silicified limestone or banded sedimentary rock with mineral veins

Weathered Sandstone Cobble

Arenite / Quartz Sandstone

Quartz-veined Mudstone or Argillite

SiO2 (Quartz) in Siltstone/Mudstone matrix

Chert (River Pebble)

Cryptocrystalline Quartz (SiO2)