Identify any rockfrom a photo.

Iron-stained quartz

Quartz (SiO₂), likely colored by iron-oxide staining

Amethyst (rough specimen)

Quartz, SiO₂; purple color commonly caused by iron-related defects and natural irradiation

Vesicular basalt (likely)

Vesicular basalt; chiefly plagioclase and pyroxene, possibly olivine, with gas-bubble vesicles

Orange calcite (rough cleavage fragment)

Calcite, CaCO₃

Amphibolite (likely)

Amphibolite, chiefly hornblende and plagioclase feldspar

Druzy quartz (quartz-lined rock fragment)

Quartz, SiO₂; likely a druzy coating on a host rock

Amber-set ring

Amber (fossilized plant resin; organic mineraloid), set in a metal ring

Orange cabochon ring

Possibly carnelian (microcrystalline quartz, SiO₂); identification from the photograph is uncertain.

Citrine quartz cluster

Quartz, silicon dioxide (SiO₂), colored by trace iron impurities

Turquoise-and-coral silver jewelry brooch

Turquoise: hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O; red cabochons appear to be coral, likely set in silver

Granite

Granite, a coarse-grained felsic intrusive igneous rock composed mainly of quartz, feldspar, and mica

Milky quartz

Quartz (silicon dioxide, SiO₂)