Identify any rockfrom a photo.

Mixed gravel and stone fragments

Unidentified lithic clasts; individual rock types cannot be determined from the image

Likely coarse-grained granite

Granite, composed mainly of quartz, feldspar, and dark mica or amphibole

Dark shale or mudstone

Fine-grained sedimentary rock composed mainly of clay minerals and quartz; exact identification is uncertain from the image.

Weathered iron-rich rock (likely limonite-stained sandstone)

Quartz-rich sandstone with iron-oxide/hydroxide staining; exact identification is uncertain from the photo

Milky quartz pebble

Quartz, silicon dioxide (SiO₂)

Conglomerate (pebble-bearing sedimentary rock)

Polymictic conglomerate; rounded clasts cemented in a finer matrix

Fossil oyster shell

Fossilized oyster (Bivalvia: Ostreidae), likely preserved as calcite-rich shell

Possible fossilized bone fragment

Indeterminate vertebrate bone; no taxonomic identification is possible from the image alone

Flint (chert)

Microcrystalline quartz (SiO₂), a variety of chert

Rounded dark pebble, likely basalt

Basalt (probable; identification is uncertain from the photo)

White quartz-rich rock, possibly vein quartz

Quartz (SiO₂), likely massive milky quartz; exact identification is uncertain from the image

Banded river pebble, likely dark chert or fine-grained quartzite

Chert (microcrystalline quartz, SiO₂) or quartzite; exact identification requires testing