Identify any rockfrom a photo.

Likely weathered quartz-rich rock, possibly smoky quartz or chert

Quartz (SiO₂), though exact identification is uncertain from the photograph

Chalcedony (likely agate/chert fragment)

Microcrystalline quartz, SiO₂

Conglomeratic breccia

Clast-supported polymictic conglomerate/breccia, cemented by silica- or carbonate-rich matrix

Tumbled smoky quartz with iron-stained inclusions

Quartz (SiO₂), likely smoky quartz variety

Likely weathered limestone or calcite-rich stone

Limestone, primarily calcium carbonate (CaCO₃), possibly calcite

Likely basalt

Basalt; fine-grained mafic volcanic rock, chiefly plagioclase and pyroxene with possible olivine

Serpentinite (probable)

Serpentinite, dominated by serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with dark magnetite or chromite and pale carbonate/talc possible

Flint or chert

Microcrystalline quartz (SiO₂), commonly with chalcedony

Quartz-rich rock, possibly milky quartz or quartzite fragment

Quartz (SiO₂), potentially quartzite if metamorphic

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate, possibly granitic gneiss

Weathered limestone or calcareous fossil fragment

Calcite-rich carbonate rock (CaCO₃), possibly fossiliferous limestone

Weathered granite or granitic pebble

Granite; chiefly quartz, alkali feldspar, plagioclase, and minor mica/amphibole