Not A Natural Rock

Polished dark stone, likely basalt

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine

Rounded granite cobble

Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende

Quartzite

Quartzite (primarily SiO2)

Pink Dyed Agate (Pink Agate Slice)

Silicon Dioxide (SiO2) - Chalcedony / Cryptocrystalline Quartz

Picture Jasper

Impure variety of silica (SiO2)

Sandstone (Quartz Sandstone)

Arenite (SiO2 based)

Tumbled Amethyst and Smoky Quartz

Silicon Dioxide (SiO2) with impurities

Citrine Quartz

Silicon Dioxide (SiO2)

Citrine Quartz

Silicon Dioxide (SiO2) with iron impurities

Citrine

Silicon Dioxide (SiO2) with iron impurities

Ferruginous Sandstone with Quartz Inclusions

Clastic Sedimentary Rock (Iron-rich Sandstone)

Granite

Phaneritic Felsic Intrusive Rock (Granite)

Turquoise

Turquoise - CuAl6(PO4)4(OH)8·4H2O

Sandstone (Ferruginous)

Clastic Sedimentary Rock (primarily SiO2 with Fe2O3 staining)

Carved Stone

Turquoise in Matrix

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

Ferruginous Sandstone (Iron-rich Sandstone)

Ferruginous Arenite

Glauconitic Sandstone (Greensand)

Glauconitic Quartz Arenite (Formula: (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)

Tumbled black-and-white stone, likely dendritic agate or jasper

Cryptocrystalline quartz (SiO₂), possibly chalcedony with manganese-oxide dendrites

Likely tumbled basalt or dark volcanic rock

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine or iron oxides

Turquoise

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

Amygdaloidal Basalt

Basalt with secondary mineral infilling

Turquoise

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

Dyed Quartz Geode

Silicon Dioxide (SiO2) with artificial pigment

Granite

Phaneritic Igneous Rock (composed of Quartz, Feldspar, and Mica/Amphibole)

Likely quartz fragment

Quartz (silicon dioxide, SiO₂), possibly milky quartz or quartz-rich rock

Rounded weathered granite (granitoid cobble)

Granite, composed mainly of quartz, feldspar, and mica/amphibole

Shale

Fissile Clay-dominant Mudrock (SiO2, Al2O3, K2O, Na2O, CaO, MgO)

Chrysocolla in Jasper (Chryso-Jasper)

Cu2-xAlx(H2-xSi2O5)(OH)4·n H2O (Chrysocolla) + SiO2 (Jasper)

Druzy Quartz Geode (likely Smokey Quartz variety)

Silicon Dioxide (SiO2) - specifically a geode formation lined with druzy quartz crystals, with a likely brownish hue indicating smokey quartz.

Pink Fluorite

Fluorite (Calcium Fluoride) - CaF2

Turquoise

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

Turquoise

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

Citrine Quartz

Silicon Dioxide (SiO2) with trace Iron impurities

Citrine Quartz

Silicon Dioxide (SiO2) with iron impurities

Rough Citrine Quartz

Silicon Dioxide (SiO2) with ferric iron impurities

Diamond

Carbon (C)

Rough Diamond

Diamond (pure Carbon, C)

Diamond

Pure Carbon (C)

Hag Stone

Porous Quartz or Chert Pebble (SiO2)

Grooved Maun Ball (Maul/Hammerstone-like Concretion)

Calcareous/Ferruginous Concretion in Sandstone Matrix

Slag Glass (Cullet)

Amorphous Silica / Glass residue