Mahogany Obsidian

Volcanic Glass (predominantly SiO2 with Hematite/Magnetite inclusions)

igneous

Rhyolite

Rhyolite (Extrusive Igneous Rock)

igneous

Quartzite

Quartzite (SiO2)

metamorphic

Basalt (Crushed Stone)

Basalt (Mafic Extrusive Igneous Rock)

igneous

Phyllite

Phyllite

metamorphic

Diabase

Diabase (also known as Dolerite)

igneous

Crushed Limestone Aggregate

Limestone (Calcium Carbonate, CaCO3)

sedimentary

Rhyolite

Rhyolite (felsic volcanic rock)

igneous

Sandstone

Arenite (SiO2-rich)

sedimentary

Granite

Phaneritic plutonic felsic igneous rock

igneous

Quartzite Cobble

Metamorphic Quartzite (SiO2)

metamorphic

Quartz (specifically Clear and Rose Quartz)

Silicon Dioxide (SiO2)

mineral

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

mineral

Geode (Unopened)

Crystalline Quartz Geode (SiO2)

sedimentary

Quartzite

Quartzite (primarily SiO2)

metamorphic

Chert (River Cobble)

Microcrystalline or cryptocrystalline Quartz (SiO2)

sedimentary

Quartzite River Rock

Metamorphic Quartzite (primarily SiO2)

metamorphic

River Cobble (likely Quartzite or Chert)

Quartzite (SiO2)

metamorphic

Golden Mica Schist

Mica Schist (primarily Muscovite/Biotite with Quartz)

metamorphic

Pyrite

Iron Disulfide (FeS2)

mineral

Tumbled Obsidian

Volcanic Glass (Silicon Dioxide)

igneous

Milky Quartz

Silicon Dioxide (SiO2)

mineral

Unakite

Unakite (metasomatized granite)

metamorphic

Milky Quartz

Silicon Dioxide (SiO2)

mineral

Mookaite Jasper

Silicified Porcellanite (SiO2 with impurities)

sedimentary

Chert (Jasper)

Silicon Dioxide (SiO2) with impurities

sedimentary

Quartzite

Quartzite (SiO2)

metamorphic

Basalt (River Cobble)

Basalt (Mafic Extrusive Igneous Rock)

igneous

Milky Quartz

Silicon Dioxide (SiO2)

mineral

Serpentinite

Serpentine rock (Mg,Fe,Ni,Al,Zn,Mn)3(Si,Al,Fe)2O5(OH)4

metamorphic

Red Jasper (possibly banded)

Silicon Dioxide (SiO2) with iron oxide inclusions

sedimentary

Milky Quartz

Silicon Dioxide (SiO2)

mineral

Quartzite

Quartzite (SiO2)

metamorphic

Quartzite

Quartzite (SiO2)

metamorphic

Rose Quartz

Silicon Dioxide (SiO2) with trace impurities of Ti, Mn, or Fe

mineral

Milky Quartz

Silicon Dioxide (SiO2)

mineral

Milky Quartz Pebble

Silicon Dioxide (SiO2)

mineral

Porphyry (likely Porphyritic Andesite or Basalt)

Porphyritic Igneous Rock

igneous

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

metamorphic

Coquina or Fossilized Shell Aggregate

Calcareous bioclastic sedimentary rock (CaCO3)

sedimentary

Vesicular Basalt with Quartz

Vesicular Basalt (SiO2 inclusions)

igneous

Coquina

Biogenic Limestone

sedimentary