Not A Natural Rock (Man Made Composite)

Granite

Granite (Phaneritic intrusive igneous rock)

River Pebbles (Quartzite / Granite Pebbles)

SiO2 (Quartz-rich detrital gravel)

River Agate (Chert/Chalcedony)

Cryptocrystalline Quartz (SiO2)

Shale

Fissile mudrock (composed primarily of clay minerals and quartz)

Granite

Granite (Phaneritic Igneous Rock)

Pumice

Pumice (volcanic glass)

Smoky Quartz

Silicon Dioxide (SiO2)

Chert (Nodular or Massive Variety)

Cryptocrystalline Quartz (SiO2)

Granite

Intrusive Phaneritic Felsic Igneous Rock

Agate (specifically, multi-colored or pastel-dyed agate)

Silicon dioxide (SiO2) - specifically, a cryptocrystalline variety of quartz known as Chalcedony, with banding classified as Agate. (If it were Fluorite, the chemical formula would be Calcium Fluoride - CaF2).

Sandstone (Quartzose Sandstone)

Sandstone (SiO2 with various trace minerals)

Sandstone (Heart-shaped pebble)

Sedimentary Quartz Sandstone

Sandstone

Sedimentary Rock (Quartz arenite)

Veined Quartzite Pebble (Heart-Shaped)

Metamorphosed quartz-rich sandstone with quartz veins

Sandstone (with Iron Staining)

Sandstone (mainly Quartz, SiO2, with Iron Oxides like Goethite/Hematite)

Shale

Shale (Lutite)

Sandstone

Arenite (SiO2 primarily)

Shale

Argillaceous Sedimentary Rock

Vesicular Basalt or Scoria

Basalt (extrusive volcanic rock)

Basalt Pebble

Basalt

Amethyst and Agate Geode Section

Silicon Dioxide (SiO2) - Crystalline Quartz and Chalcedony

Granite

Felsic Intrusive Igneous Rock

Sandstone

Sedimentary Rock (Quartz arenite)

Sandstone

Sandstone (composed predominantly of SiO2)

Red Sandstone

Arenite (primarily Quartz with Hematite cement)

Beach Pebble (Basalt / Greywacke Gravel)

Mafic Volcanic Rock (Basalt)

Shale

Laminated Fissile Pelite

Obsidian

Volcanic Glass

Sandstone (Quartzose)

Arenite (primarily SiO2)

Chert (Jasper/Agate variety)

Silicon Dioxide (SiO2)

Conglomerate

Conglomerate (Sedimentary Clastic Rock)

Sandstone

Sandstone (SiO2-rich framework with variable matrix)

Tumbled River Pebble (Quartzite / Agate)

Silicon Dioxide (SiO2)

Sandstone (likely Arkose or Quartz Sandstone)

Clastic sedimentary rock (primarily SiO2)

Clear Quartz (Cut/Faceted Gemstone)

Silicon Dioxide (SiO2)

Greenstone

Metamorphic mafic rock (chlorite-actinolite-epidote schist)

Pink Granite

Intrusive Igneous Rock (high K-feldspar content)

Diabase (Dolerite)

Diabase or Dolerite

Shale

Fissile Mudstone (primarily composed of phyllosilicate minerals like kaolinite, montmorillonite, and illite)

Vesicular Basalt (Lava Rock)

Vesicular basalt

Shale

Shale (Fissile Mudstone)

Sandstone

Arenite