Identify any rockfrom a photo.

Polished pink granite (likely granite pebble)

Granite, mainly quartz, alkali feldspar, plagioclase, and minor biotite/hornblende

Milky quartz with iron-oxide staining

Quartz, silicon dioxide (SiO₂), commonly with hematite/goethite inclusions

Quartz crystal with iron-oxide staining

Quartz (SiO₂), likely iron-stained or included quartz

Milky quartz in weathered host rock

Quartz, silicon dioxide (SiO₂), likely with iron-stained feldspar or altered matrix

Likely weathered gray limestone or shale fragment

Calcite-rich carbonate rock (limestone), possibly calcareous shale

Rounded river pebbles, likely basalt and sandstone/conglomerate

Probable basalt (dark specimen) and ferruginous sandstone or weathered conglomerate (tan specimen)

Rounded dark mafic cobble, likely basalt

Basalt; primarily plagioclase feldspar, clinopyroxene, and commonly olivine or magnetite

Water-worn limestone and calcite-rich stones

Limestone, chiefly calcite (CaCO₃), with possible dolomite and minor iron-oxide staining

Polished jasper pebble (likely brecciated or ocean jasper)

Jasper, microcrystalline quartz (SiO₂) with iron-oxide impurities

Dark mafic rock, likely basalt

Basalt; chiefly plagioclase feldspar and pyroxene, with possible olivine and iron oxides

Likely polished quartz-rich stone or calcite specimen

Uncertain; possibly quartz (SiO₂) or calcite (CaCO₃)

Quartz-rich granitic rock (likely weathered granite)

Granite; chiefly quartz, feldspar, and mica, with possible iron-oxide staining