Identify any rockfrom a photo.

Iron-stained quartz-rich rock, possibly ferruginous quartzite

Quartz-rich ferruginous rock; exact identification is uncertain from the photograph

Tumbled brown agate

Microcrystalline quartz (SiO₂), a variety of chalcedony

Likely tumbled brown agate

Microcrystalline quartz (SiO₂), commonly chalcedony; exact identification is uncertain from the image

Tumbled reddish-brown stone, likely carnelian

Chalcedony, a microcrystalline variety of quartz (SiO₂)

Rose quartz heart carving

Quartz (silicon dioxide, SiO₂), pink variety known as rose quartz

Ironstone concretion (possibly a limonite/goethite-rich nodule)

Iron-oxide/hydroxide concretion, commonly composed of goethite (α-FeO(OH)) and/or limonite; exact identification requires testing

Greenstone (likely chlorite-rich metamorphic rock)

Chlorite-rich greenschist; commonly composed of chlorite, actinolite, and epidote

Likely sandstone pebble

Quartz-rich sandstone (composition uncertain from the image)

Vesicular volcanic rock (possibly scoria)

Scoria, a vesicular basaltic to andesitic volcanic rock

Iron-rich mineral specimen, possibly magnetite-rich ore

Possibly magnetite (Fe₃O₄), with associated iron oxides; identification is uncertain from the photograph

Possible sea glass (naturally frosted glass), not a confirmed geological specimen

Man-made silicate glass; composition varies, commonly soda-lime glass

Likely fine-grained sandstone pebble

Quartz-rich sandstone; exact composition cannot be confirmed from the image