Rock

Yellow Chert or Jasper

Microcrystalline Quartz (SiO2)

River Pebble (Quartz/Jasper)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Fossiliferous Chert with Brachiopod Impression

Chert (SiO2) containing Brachiopoda fossil remains

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Banded Gneiss / Veined Metamorphic Pebble

Metamorphic Rock with Quartz/Feldspar Veins

Clam Fossil

Bivalvia fossil

Fossilized Bone

Fossilized vertebrate bone

Bivalve Seashell Fossil

Class Bivalvia

Granite Pebble

Intrusive Igneous Rock

Greenish metamorphic rock (possibly chlorite schist)

Chlorite-rich schist; exact identification is uncertain from the image

Quartz-bearing rock fragment

Likely quartz with iron-oxide staining; exact rock type cannot be determined from the image

Shale

Lutaceous sedimentary rock

White Quartz

Silicon Dioxide (SiO2)

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Granite

Intrusive Igneous Rock

Scoria

Scoria

Painted River Rock

Painted Quartzite or Smooth Siltstone

Weathered granite

Granite; chiefly quartz, potassium feldspar, plagioclase, and biotite/hornblende

Biotite-bearing granite or granitic gneiss

Quartz–feldspar–biotite granitoid; exact identification requires testing

Red granite or granitic gneiss cobble

Quartz–feldspar–mica rock; likely granite, possibly gneiss

Pink-and-black granite

Biotite-bearing granite, chiefly quartz, feldspar, and biotite mica

Weathered limestone

Calcite-rich limestone (CaCO₃), possibly fossiliferous or dolomitic

Orbicular granite (likely rapakivi-type granite)

Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende

Slickenside

Tectonic Fault Scarp Surface

Greenstone (likely altered mafic rock)

Chlorite- and amphibole-bearing metabasalt; exact identification requires testing

Weathered sandstone block

Quartz-rich sandstone; exact composition cannot be confirmed from the image

Granite Pebble

Granite

Unidentified Rock

Unknown

Banded river pebble (likely greenstone)

Likely chlorite- and amphibole-rich greenstone; exact identification requires testing

Carnelian agate

Cryptocrystalline quartz (SiO₂), iron-oxide-bearing chalcedony

Quartz-veined metamorphic rock, likely quartzite or schist

Quartz-rich metamorphic rock with a milky-quartz vein; exact host rock is indeterminate from the photo

Alluvial stream gravel (mixed rock specimens)

Polymictic fluvial deposit; likely mixtures of quartzite, sandstone, shale, chert, basalt, and granite-derived minerals

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate, possibly altered granite

Quartz-rich gravel fragment

Quartz (silicon dioxide, SiO₂), possibly with feldspar or carbonate inclusions

Quartz Vein in Basalt

Silicon Dioxide (SiO2) in Mafic Igneous Rock

Shale

Mudrock / Pelite

River Rocks (Black)

Various lithologies (e.g., basalt, chert, obsidian for black varieties), mechanically rounded clasts

Coarse-grained granite or granitic pegmatite fragment

Granite; primarily quartz, feldspar, and mica

Weathered limestone or dolostone

Calcite-rich limestone (CaCO₃), possibly dolomite-bearing

Pink Granite

Phaneritic Quartz-Feldspar Plutonic Rock

Shale

Shale (clastic sedimentary rock composed of silt and clay-sized particles)