Man Made Rock Like Material

Granite (Alkali-feldspar Granite)

Felsic Plutonic Rock (Primary minerals: Quartz SiO2, Orthoclase KAlSi3O8, Plagioclase (Na,Ca)AlSi3O8)

Quartzite Pebble

Quartzite (SiO2 with minor impurities)

Sandstone

Arenite (composed primarily of SiO2)

Gold

Native Gold (Au)

Limestone (specifically Chalky Limestone)

Calcium Carbonate (CaCO3 / Calcite)

Sandstone

Arenite (SiO2 based)

Basalt

Extrusive mafic igneous rock

White Marble

Recrystallized Calcite (CaCO3)

Chert (or possibly Flint)

Chert (variant: Flint)

Granite

Granite (a plutonic igneous rock composed of quartz, feldspar, and mica)

Veined Quartz

SiO2 (Silicon Dioxide)

Conglomerate

Conglomerate (clastic sedimentary rock)

River Cobble (Quartzite with Iron Staining)

Metamorphic Quartzite (SiO2 with Fe2O3 inclusions)

Red Sandstone

Arenite (ferruginous sandstone)

Quartz (likely Milky Quartz or Chalcedony)

Quartz (SiO2 - Silicon Dioxide)

Sandstone (Ferruginous)

Sandstone (primarily SiO2 with Iron Oxide cement)

Granite

Phaneritic Felsic Igneous Rock (primarily SiO2, Al2O3, K2O, Na2O)

Copper-bearing Quartz (with Malachite and Iron Oxides)

Quartz (SiO2) with Malachite (Cu2CO3(OH)2) and Hematite/Limonite (Fe2O3)

Granite (weathered/river-tumbled)

Granite (Plutonic Igneous Rock)

Fire Opal (in matrix)

Hydrated Silica (SiO2·nH2O)

Peridotite (Pyroxenite/Serpentinized Dunite)

Ultramafic Rock (consisting primarily of Olivine and Pyroxene)

Turquoise

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

Quartzite

Quartzite (primarily SiO2)

Petrified Wood

Silicified Wood (SiO2)

Schist

Mica Schist (Medium-grade metamorphic rock)

Sandstone

Arenite (primarily SiO2 with trace Fe2O3)

Granodiorite

Granodiorite (Intermediate intrusive igneous rock)

Quartz (Iron-Stained)

Silicon Dioxide (SiO2)

Chert (Field-collected Arrowhead-shaped Fragment)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz Vein in Metamorphic Rock

Silicon Dioxide (SiO2) within Metasedimentary host

Slate

Slate (foliated metamorphic rock, primarily composed of quartz, illite, chlorite, and micas)

Quartzite

Quartzite (primarily SiO2)

Petrified Wood

Silicified Wood (primarily SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Sandstone (Quartzose Sandstone)

Arenite (primarily SiO2 with minor Fe2O3)

Ironstone Concretion / Limonite Node

Ferruginous Sedimentary Rock (composed primarily of Limonite FeO(OH)·nH2O and Goethite)

Granite Cobble

Phaneritic Felsic Igneous Rock (Granite)

Sandstone (Yellow/Tan)

Clastic sedimentary rock (primarily SiO2 with iron oxide staining)

Limestone

Sedimentary Calcite (CaCO3)

River Stone (River Pebbles)

Alluvial Deposit (typically Quartzite, Sandstone, or Granite clasts)

Sandstone with Liesegang Rings

Arenite with Iron Oxide Concretions

Ferrochrome Slag

Anthropogenic silicate/oxide glass (Complex silicate matrix with Cr-Fe-Si inclusions)