Identify any rockfrom a photo.

Coarse-grained gray metamorphic rock, likely gneiss or granitic gneiss

Quartz–feldspar–mica gneiss; exact identification requires petrographic or chemical testing

Fossilized shell, likely gastropod or bivalve

Recrystallized carbonate fossil; original shell likely aragonite or calcite (taxon indeterminate)

Weathered metallic rock, possibly iron-rich ore

Uncertain; possible goethite–hematite limonite or iron-nickel meteorite

Fossil oyster shell

Fossilized bivalve, commonly Ostrea or Crassostrea

Fossiliferous limestone

Bioclastic limestone, predominantly calcite (CaCO₃)

Fossilized gastropod (snail)

Gastropoda; shell commonly preserved as calcite (CaCO₃)

Fossil-rich limestone

Bioclastic limestone, likely containing bivalve or brachiopod fossils; calcium carbonate (CaCO₃), chiefly calcite

Banded chert or siliceous shale

Microcrystalline quartz (SiO₂), possibly interbedded with carbonaceous or clay-rich shale

Quartz-bearing pegmatitic rock, likely granite/pegmatite

Feldspar–quartz pegmatite; chiefly K-feldspar, plagioclase, quartz, and possible mica

Polished black stone, possibly basalt or black obsidian

Likely fine-grained basalt (plagioclase and pyroxene) or volcanic glass (obsidian; rhyolitic composition)

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂), with possible feldspar, mica, and iron-oxide staining

Pegmatitic granite

Granite, composed mainly of quartz, feldspar, and mica