Not A Natural Rock (Man Made Composite)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Basalt (River Pebble)

Mafic volcanic rock (primarily Plagioclase feldspar and Pyroxene)

Granite

Phaneritic plutonic rock (primarily Quartz, Alkali Feldspar, and Plagioclase)

Turquoise

Turquoise (Hydrated phosphate of copper and aluminium), CuAl6(PO4)4(OH)8·4H2O

Sandstone

Sandstone (lithified quartz arenite, arkose, graywacke, etc. depending on composition)

Silicon Carbide (Carborundum)

Silicon Carbide (SiC)

Chalcedony (or a variety of Chalcedony, likely Agate or Jasper)

Chalcedony (SiO₂)

Granite

Granite (compositional mixture of Quartz, Feldspar, and Mica)

Citrine

SiO2 (Silicon Dioxide)

Sandstone

Sandstone (lithified sand)

Limonite (Iron Ore)

Limonite (Hydrous iron(III) oxide-hydroxide mixture, primarily FeO(OH)·nH2O)

Slate

Foliated Metamorphic Rock (composed primarily of Quartz, Muscovite, and Illite)

Sandstone

Arenite (composed primarily of SiO2)

Pink Granite

Phaneritic intrusive felsic igneous rock

Green Aventurine

Aventurine Quartz (SiO2 with inclusions)

Turquoise

Hydrated phosphate of copper and aluminium: CuAl6(PO4)4(OH)8·4H2O

Granite

Phaneritic Felsic Igneous Rock (primarily Quartz, Feldspar, and Mica)

US Penny

Cuprum (Copper: Cu) and Zincum (Zinc: Zn) Alloy

Conglomerate

Conglomerate (clastic sedimentary rock)

Limestone (Porous/Travertine variant)

Sedimentary Calcium Carbonate (CaCO3)

Sandstone

Arenite (SiO2 based clastic rock)

Granite

Phaneritic Igneous Rock (composed of quartz, alkali feldspar, and plagioclase)

Chevron Amethyst

Silicon Dioxide (SiO2) with iron impurities

Pumice

Pumice (a highly vesicular extrusive igneous rock)

Blue Howlite (Dyed)

Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)

Granite

Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Jasper and Yellow Chert (Tumbled)

Microcrystalline Quartz (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Green Aventurine

Silicon Dioxide (SiO2) with Fuchsite inclusions

Ironstone Concretion / Goethite-Hematite Nodule

Goethite/Hematite (α-FeO(OH) / Fe2O3)

Chevron Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hag Stone (Banded Chert or Limestone with Borehole)

Microcrystalline Quartz (Chert) or Calciferous Siltstone (CaCO3/SiO2)

Glauconite (Glauconitic Sandstone)

Glauconite [(K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2]

Clear Quartz

Silicon Dioxide (SiO2)

Quartz (Smoky/Milky Pebble)

Silicon Dioxide (SiO2)

Sandstone

Arenite (SiO2 primarily)

Conglomerate

Conglomerate (clastic sedimentary rock)

Dyed Agate Geode (Pink/Magenta)

Silicon Dioxide (SiO2) - variety of Chalcedony/Quartz

Limonite (Iron Ore)

Hydrous Iron Oxide (goethite, lepidocrocite)

Grooved Maun Ball (Maul/Hammerstone-like Concretion)

Calcareous/Ferruginous Concretion in Sandstone Matrix

Granite

Granite (phaneritic intrusive igneous rock consisting mainly of quartz, alkali feldspar, and plagioclase)

Granite

Granite (Mainly Quartz, Feldspar, and Mica)