Identify any rockfrom a photo.

Dark igneous rock with white feldspar/quartz patches

Likely porphyritic basalt or andesite; white patches may be plagioclase feldspar or quartz

Weathered quartz-rich pebble

Likely quartzite or quartz-rich sandstone; exact identification is uncertain from the photo

Diamond (or Cubic Zirconia / Rhinestones)

Carbon (C) or Zirconium dioxide (ZrO2)

Rounded river pebble, likely quartz-rich sandstone

Quartz-rich sandstone (tentative; exact identification is limited from the image)

Rounded quartzite pebble

Quartzite, composed predominantly of quartz (SiO₂)

Fossiliferous limestone

Calcite-rich limestone (predominantly CaCO₃), with possible fossil fragments

Sandstone (Cut Dimension Stone)

Arenite / Quartzose Sandstone (primarily SiO2)

Possible iron-rich meteorite fragment

Unclassified suspected meteorite; composition cannot be determined from the photograph

Quartzite cobble (probable)

Quartzite, composed predominantly of recrystallized quartz (SiO₂)

Pegmatite

Granitic pegmatite, composed mainly of quartz and feldspar with possible mica

Pumice

Pumice, vesicular volcanic glass, commonly rhyolitic to dacitic in composition

Pegmatitic granite (quartz–feldspar–mica rock)

Granitic pegmatite; chiefly quartz (SiO₂), potassium feldspar and plagioclase, with dark mica such as biotite