Basalt

Basalt (Mafic Extrusive Igneous Rock)

igneous

Basalt

Basalt (composition of plagioclase, pyroxene, and olivine)

igneous

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

metamorphic

Quartzite (River Cobble)

Quartzite (SiO2)

metamorphic

Chert (Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

sedimentary

Basalt

Basalt

igneous

Sandstone (Quartzose Pebble)

Clastic Sedimentary Rock (Litharenite/Quartz arenite)

sedimentary

Quartzite

Quartzite (SiO2)

metamorphic

Chert (Flint)

Chert (SiO2)

sedimentary

Yellow Quartzite

Quartzite (SiO2)

metamorphic

Granite Tile (Commercial Granite)

Granite (Phaneritic Quartz-Feldspar Plutonic Rock)

igneous

Carnelian Agate

Carnelian (Silicon Dioxide, SiO2)

mineral

Carnelian (Agate/Chalcedony)

Silicon Dioxide (SiO2)

mineral

Quartzite

Quartzite (SiO2)

metamorphic

Gneiss

Gneiss (High-grade metamorphic rock)

metamorphic

Basalt

Basalt (Mafic Extrusive)

igneous

Granite

Granite (Felsic intrusive igneous rock)

igneous

Diorite (River Cobble)

Intermediate plutonic igneous rock

igneous

Milky Quartz

Silicon Dioxide (SiO2)

mineral

Sandstone (likely Arkosic or Quartzose)

Sandstone (SiO2 with inclusions)

sedimentary

Sandstone (Ferruginous)

Arenite (primarily SiO2 with iron oxide cement)

sedimentary

Sandstone (Ferruginous)

Arenite (primarily SiO2 with iron oxide cement)

sedimentary

Pink Granite

Granite (Felsic Plutonic Rock)

igneous

Smoky Quartz

Smoky Quartz (Silicon Dioxide - SiO2)

mineral

Granite

Granite (Felsic intrusive igneous rock)

igneous

Granite

Phaneritic Felsic Igneous Rock (Granite)

igneous

Granitoid (Granite/Gneiss)

Granitoid silicate rock, primarily quartz and feldspar

igneous/metamorphic

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

mineral

Limonitic Sandstone (Stained Sandstone)

Clastic Sedimentary Rock with Iron Oxide (Limonite/Goethite) staining

sedimentary

Granite

Granite (Felsic intrusive igneous rock)

igneous

Granite

Granite (Phaneritic Igneous Rock)

igneous

Rough Diamond

Diamond (pure Carbon, C)

mineral

Pyrite in Matrix (likely Quartz or Schist matrix)

Iron Sulfide (FeS2)

mineral

Amethyst (Quartz variety)

Silicon Dioxide (SiO2) with iron impurities

mineral

Chert (Honey Chert or Chalcedony Pebble)

Cryptocrystalline Quartz (SiO2)

sedimentary

Amber

Amber (C10H16O)

mineral

Agate (Moss or Lake Superior type)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

mineral

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

mineral

Pyrite

Iron Sulfide (FeS2)

mineral

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

mineral

River Pebbles (Sandstone and Quartzite)

SiO2 (Quartz) dominated clastic rocks

sedimentary and metamorphic

Peach Moonstone

Potassium Aluminum Silicate (KAlSi3O8); variety of Orthoclase Feldspar

mineral