Quartzite

Quartzite (SiO2)

metamorphic

Peach Moonstone (Feldspar variety)

Orthoclase Feldspar (KAlSi3O8) with inclusions

mineral

Granite Cobble

Granite (Phaneritic Igneous Rock)

igneous

Sandstone with Quartz Vein

Arenite with SiO2 intrusion

sedimentary

Quartz Druze on Matrix

Silicon Dioxide (SiO2)

mineral

Quartzite

Quartzite (primarily SiO2)

metamorphic

Carnelian (Red Chalcedony)

Silicon Dioxide (SiO2)

mineral

Mahogany Obsidian

Volcanic Glass (Silicate: SiO2 + Fe2O3)

igneous

Mookaite Jasper

Mookaite (variety of Chert/Jasper), Silicon Dioxide - SiO2

sedimentary

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

mineral

Bumblebee Jasper

Volcanic Tuff (mixture of Quartz, Sulfur, Hematite, and Orpiment)

igneous

Yellow Quartzite (River Cobble)

Quartzite (SiO2)

metamorphic

Basalt

Vesicular Basalt

igneous

Basalt

Basalt (Extrusive Mafic Igneous Rock)

igneous

Chert (Nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

sedimentary

Chert (Nodule)

Silicon Dioxide (SiO2)

sedimentary

Chert (River Pebble)

Chert (SiO2)

sedimentary

Granite Cobble (River Stone)

Felsic intrusive igneous rock (composition: Quartz, Feldspar, Mica)

igneous

Basalt

Basalt (composition of plagioclase feldspar and pyroxene)

Igneous

Pink Granite

Phaneritic Felsic Igneous Rock (Granite)

igneous

Basalt with Plagioclase Phenocrysts (Porphyritic Basalt)

Porphyritic Basalt (Mafic volcanic rock)

igneous

Fossiliferous Limestone (Crinoidal Limestone)

Biogenic Limestone (Calcium Carbonate, CaCO3)

sedimentary

Porphyry

Porphyritic Rhyolite or Andesite

igneous

Sandstone (Quartzose)

Arenite (primarily SiO2)

sedimentary

Quartzite

Quartzite (SiO2)

metamorphic

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

mineral

Jasper

Silicon dioxide (SiO2)

sedimentary

Diabase (Greenstone Pebble)

Diabase or Dolerite

igneous

Microcrystalline Limestone Pebble

Carbonate sedimentary rock (Calcium Carbonate, CaCO3)

sedimentary

Diorite (Salt and Pepper Rock)

Diorite

igneous

Granodiorite Pebble

Granodiorite

igneous

Granite

Felsic Plutonic Rock (primarily SiO2)

igneous

Pink Granite

Granite (Alkali-feldspar granite)

igneous

Diorite (River Cobble)

Intermediate plutonic igneous rock

igneous

Diorite

Diorite (intermediate intrusive igneous rock)

igneous

Ironstone Concretion (Moqui Marble)

Hematite/Goethite Concretion (Fe2O3 / FeO(OH))

sedimentary

Diorite (Salt and Pepper Rock)

Diorite

igneous

Pink Granite

Granite (Phaneritic Quartz-Feldspar rock)

igneous

Diorite

Diorite (Intermediate intrusive igneous rock)

igneous

Quartz Pebble

Silicon Dioxide (SiO2)

mineral

Pink Granite

Phaneritic Plutonic Felsic Rock (Granite)

igneous

Gneiss (specifically a water-worn pebble)

Gneiss

metamorphic