Rock (Likely Sedimentary)

River Pebble (likely Quartzite or Siltstone)

Sedimentary Clast (SiO2 based)

Small weathered stone, likely sandstone or limestone fragment

Indeterminate clastic or carbonate rock; mineral composition cannot be confirmed from the image

Sandstone (likely Conglomerate or Gritstone)

Arenite (SiO2 based)

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

Polished green banded stone, likely serpentine or altered greenstone

Probable serpentinite/greenstone; commonly dominated by serpentine-group minerals, chlorite, epidote, or actinolite

Chert (Jasper)

Microcrystalline Quartz (SiO2) with iron oxide impurities

Sandstone (likely a river or beach pebble)

Sandstone (a clastic sedimentary rock)

Coal (most likely Bituminous or Anthracite)

Coal (organic sedimentary rock)

Quartz geode

Microcrystalline quartz (SiO₂), commonly with chalcedony and possible calcite inclusions

Fossiliferous Shale

Fossiliferous Mudstone / Shale

Sandstone (likely Arkosic or Ferruginous)

Arenite (SiO2 with iron oxides or feldspar)

Weathered granitic cobble

Granite, composed mainly of quartz, feldspar, and mica/amphibole

Sandstone River Pebble

Arenite (SiO2 predominantly)

Red sandstone with pale weathered surface

Iron-oxide-stained quartz arenite (sandstone)

Banded dark pebble (likely gneiss or banded metamorphic rock)

Indeterminate from the image; possibly banded gneiss

Likely weathered sandstone or iron-stained sedimentary pebble

Indeterminate clastic sedimentary rock; possibly quartz-rich sandstone

Porous fossil coral fragment

Fossilized colonial coral; precise taxon cannot be determined from the image

Sandstone (Ferruginous)

Arenite with Iron-Oxide Cement

Polished banded gneiss pebble

Gneiss, chiefly quartz–feldspar–mica; exact mineralogy uncertain from image

Rounded river pebbles (mixed lithologies)

Water-worn clasts; individual stones cannot be identified precisely from the image

Conglomerate

Clastic sedimentary rock (Conglomerate)

Gneiss (Granitic Gneiss)

Gneiss

Quartz Vein in Siltstone

Silicon Dioxide (SiO2) within Sedimentary/Metamorphic Matrix

Quartz-rich mineral fragment

Quartz (silicon dioxide, SiO₂), possibly milky quartz

Sandstone River Cobble

Arenite (SiO2 based)

Likely graywacke (feldspathic sandstone)

Lithified sandstone, likely a feldspathic or lithic wacke; exact identification requires closer examination

Sandstone (likely Quartzose Sandstone)

Arenite (SiO2 based)

Small gray rock fragment, possibly limestone or marl

Undetermined carbonate-rich sedimentary rock; composition cannot be confirmed visually

Geode (Unopened)

Silicon Dioxide (SiO2) in sedimentary vugs

Weathered limestone (tentative)

Calcite-rich limestone, chiefly calcium carbonate (CaCO₃)

Fine-grained, foliated rock (possibly slate or phyllite)

Undetermined; likely slate or phyllite, composed mainly of quartz, mica, and chlorite

Rounded quartz-rich pebble, possibly chert or quartzite

Indeterminate; likely microcrystalline quartz (SiO₂) or quartzite

Fossil brachiopod shell

Brachiopoda; exact genus/species indeterminate

Chalcedony/Agate

Cryptocrystalline Silica (SiO2)

Vuggy Quartz on Matrix

Silicon Dioxide (SiO2)

Weathered sandstone or limestone fragment

Likely quartz-rich sandstone or micritic limestone; exact identification requires testing

Chert (Nodular)

Microcrystalline Silica (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Sandstone (Quartz-rich)

Clastic sedimentary rock (SiO2 primary)

Likely banded gneiss

Gneiss (quartz–feldspar–mica-rich rock; exact identification uncertain from the photo)

Concretion

Septarian concretion (likely containing Calcite or Siderite)

Weathered sandstone or iron-stained sedimentary rock

Quartz-rich sandstone, likely limonitic/goethitic cement