Not A Rock (Man Made Polymer)

Basalt with Vesicle/Vug

Basalt (Aphanitic Mafic Igneous Rock)

Granite

Granite (Mainly Quartz, Alkali Feldspar, and Plagioclase)

Chert (Flint Nodules)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint Nodules)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Scoria (Lava Rock)

Vesicular Basalt / Scoria

Scoria (Lava Rock)

Mafic extrusive volcanic rock (Scientific formula varies based on mineral content: primarily SiO2, MgO, and FeO)

Schist

Mica Schist

Quartzite (River Cobble)

SiO2 (Quartz-rich Metamorphic Rock)

Basalt with Quartz Veining

Basalt (Mafic Volcanic Rock with SiO2)

Granite

Granite (Phaneritic intrusive igneous rock)

Tiger's Eye (Rough)

Pseudomorph of Quartz after Crocidolite (SiO2 with FeOOH inclusions)

Limonite-stained Quartz

Silicon Dioxide (SiO2) with Iron Oxide/Hydroxide (FeO(OH)·nH2O) staining

Quartz (Milky/Common)

Silicon Dioxide (SiO2)

Iron-Stained Quartz (Riverside Cobble)

Silicon Dioxide (SiO2) with Limonite/Hematite inclusions

Sandstone (Ferruginous)

Sandstone (Clastic sedimentary rock, predominantly SiO2 with Fe2O3 cement)

Andesite

Andesite (Intermediate Extrusive Volcanic Rock)

Yellow Quartzite

Quartzite (SiO2)

Gneiss Pebble

Gneiss

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Scoria (Red Lava Rock)

Scoria

Basalt

Basalt (Aphanitic Mafic Volcanic Rock)

Basalt (Porphyritic Basalt)

Porphyritic Basalt (Mafic volcanic rock)

Basalt

Basalt (Mafic Extrusive Igneous Rock)

Basalt

Vesicular Basalt (Mafic volcanic rock)

Sandstone

Arenite (primarily SiO2)

Quartzite (River Pebble)

Recrystallized Quartz (SiO2)

Travertine

Terrestrial Sedimentary Rock (Calcium Carbonate, CaCO3)

Quartzite Pebble

Quartzite (primarily SiO2)

Sandstone (Ferruginous)

Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz (Milky Quartz / Quartzite)

Silicon Dioxide (SiO2)

Gemstone Sand (Mineral Assortment)

Mixed Mineral Concentrates (Commonly including Quartz SiO2, Garnet X3Y2(SiO4)3, and Tourmaline (Na,Ca)(Li,Mg,Al)3(Al,Fe,Mn)6(BO3)3(Si6O18)(OH,F)4)

Scoria (Lava Rock)

Aphanitic vesicular mafic igneous rock

Conglomerate (River Rock)

Clastic sedimentary rock (primarily SiO2)

Scoria (Lava Rock)

Scoria (Vesicular Basaltic Glass/Rock)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Limestone

Calcium Carbonate (CaCO3)

Pink Quartzite

Quartzite (mainly SiO2 with iron oxide impurities)

Sandstone (specifically an Iron-Concretion)

Arenite with Iron Oxide (Limonite/Goethite) cementation

Basalt

Basalt (Composition primarily Plagioclase feldspar, Pyroxene, and Olivine)

Gneiss

Gneiss (High-grade metamorphic rock)

Granite

Phaneritic intrusive igneous rock (composed mainly of Quartz SiO2, Feldspar KAlSi3O8, and Biotite/Mica)