Identify any rockfrom a photo.

Weathered granite fragments

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

Pegmatite fragment

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

Iron-stained quartz or quartzite fragment

Likely quartz (SiO₂), possibly iron-oxide-stained quartzite; exact identification is uncertain from the image

Weathered granite fragment

Granite, a coarse-grained felsic intrusive igneous rock; likely quartz, feldspar, and mica

Iron-stained sandstone

Quartz-rich sandstone with iron-oxide staining (quartz, SiO₂; hematite/goethite, Fe₂O₃/FeO(OH))

Petrified wood

Silicified fossil wood; commonly quartz (SiO₂) replacing wood tissue

Likely amber cabochon ring

Amber, fossilized tree resin (organic mineraloid; not a mineral)

Blue-stone and diamond ring

Blue stone is possibly blue sapphire (corundum, Al₂O₃); surrounding stones appear to be diamonds (carbon, C).

Color-change garnet (likely alexandrite-like garnet)

Likely pyrope–spessartine garnet; exact species cannot be confirmed from the image

Garnet-set gold ring

Likely almandine garnet, Fe₃Al₂(SiO₄)₃; the image does not establish the stone’s identity or treatment

Diamond-set gold ring or ring component

Diamond (crystalline carbon, C); gold alloy setting (Au)

Porphyritic volcanic rock (likely rhyolite or andesite)

Porphyritic felsic-to-intermediate volcanic rock; exact identification requires closer examination