Sandstone

Arenite (SiO2 based)

sedimentary

Quartzite

Quartzite (Primary mineral: SiO2)

metamorphic

Porphyry

Porphyritic Andesite/Basalt

igneous

Porphyritic Andesite

Andesite (porphyritic variety)

igneous

Quartzite

Quartzite (primarily SiO2)

metamorphic

Quartzite

Quartzite (primarily SiO2)

metamorphic

Red Sandstone

Arenite (high iron oxide content)

sedimentary

Red Sandstone

Arenite (Ferruginous Sandstone)

sedimentary

Sandstone

Arenite (primarily SiO2)

sedimentary

Quartzite

Quartzite (chiefly SiO2)

metamorphic

Quartzite with inclusions

Quartzite (primarily SiO2)

metamorphic

Chert (Jasper variety)

Silicon Dioxide (SiO2)

sedimentary

Quartzite

Quartzite (primarily SiO2)

metamorphic

Quartzite

Quartzite (primarily SiO2)

metamorphic

Greenstone

Protolith of basalt, diabase, or gabbro; often contains minerals like chlorite, actinolite, and epidote

metamorphic

Sandstone

Arenite (SiO2 primarily)

sedimentary

Basalt

Mafic volcanic rock (Basalt)

igneous

Sandstone

Arenite (Clastic Sedimentary Rock)

sedimentary

Vesicular Basalt

Vesicular Basalt (Aphanitic Mafic Igneous Rock)

igneous

Quartzite

Quartzite (primarily SiO2)

metamorphic

Chert (Jasper/Flint variety)

Silicon Dioxide (SiO2)

sedimentary

Quartzite

Quartzite (SiO2)

metamorphic

Chert (Jasper)

Microcrystalline Quartz (SiO2)

sedimentary

Quartzite

Quartzite (primarily SiO2)

metamorphic

Quartzite

Quartzite (SiO2)

metamorphic

Quartz Vein in Host Rock (clastic sediment)

Silicon Dioxide (SiO2) in matrix

sedimentary

Greywacke

Dirty Sandstone (Lithic wacke)

sedimentary

Sandstone Concretion

Sedimentary Concretion (SiO2 or CaCO3 cemented)

sedimentary

Serpentinite

Serpentinite (composed primarily of Serpentine group minerals, Mg3Si2O5(OH)4)

metamorphic

Greenschist

Chlorite schist

metamorphic

Greywacke

Greywacke sandstone

sedimentary

Quartzite

Quartzite (SiO2)

metamorphic

Milky Quartz with Inclusions

Silicon Dioxide (SiO2)

mineral

Ambergris

Ambergris (Coprolite-adjacent/Organic secretion)

mineraloid

Quartzite

Quartzite (primarily SiO2)

metamorphic

Ambergris (Sea Wax)

Physeter macrocephalus fecalith

Organic geological/oceanic specimen

Granite Cobble

Plutonic Igneous Rock (Granitic)

igneous

Granite Cobble

Granite (Phaneritic Igneous Rock)

igneous

Felsic Igneous Rock (likely Rhyolite or weathered Granite)

Felsic Volcanic/Plutonic Rock

igneous

Sandstone (Ferruginous)

Ferruginous Sandstone (SiO2 with Fe2O3)

sedimentary

Gneiss

Gneiss (High-grade Metamorphic Rock)

metamorphic

Ambergris

Ambrein-rich Calculus

Organic (Pseudo-geological)