Identify any rockfrom a photo.

Gray metamorphic rock, likely slate or phyllite

Probably quartz–mica phyllite or fine-grained slate; exact identification requires testing

Weathered quartz-rich rock, likely chert or quartzite

Microcrystalline quartz (SiO₂), possibly with iron-oxide staining

Carved stone bowl or mortar

Uncertain; likely steatite (soapstone) or fine-grained volcanic stone

Vesicular basalt (scoria-like volcanic rock)

Basalt, chiefly plagioclase feldspar, pyroxene, and iron-rich minerals; abundant vesicles from escaping volcanic gas

Banded gneiss

Gneiss, commonly quartz–feldspar–mica gneiss

Tumbled yellow translucent mineral, likely citrine or honey calcite

Citrine: quartz, SiO₂; honey calcite: calcium carbonate, CaCO₃

Small orange-red tumbled gemstones, likely carnelian

Carnelian, a microcrystalline variety of quartz (SiO₂), typically colored by iron oxides

Likely tumbled carnelian or orange chalcedony

Microcrystalline quartz, SiO₂ (chalcedony variety)

Small tumbled orange-brown mineral fragment

Indeterminate; possibly iron-stained quartz, carnelian, or orange calcite

Mixed tumbled gravel and quartz-rich sandstone

Primarily quartz (SiO₂), feldspar, and lithic sedimentary fragments; one piece appears to be quartz-rich sandstone

Dark coarse-grained metamorphic rock, likely amphibolite or hornblende schist

Amphibolite, dominated by hornblende amphibole and plagioclase feldspar; exact identification requires testing

Crushed basalt and andesite aggregate

Basalt–andesite volcanic rock; primarily plagioclase feldspar, pyroxene, and minor olivine or amphibole