Igneous And Metamorphic Derivative (Weathered)

Chert (specifically Flint)

Microcrystalline quartz (SiO2)

Aventurine Quartz

Silicon Dioxide (SiO2) with inclusions (typically Fuchsite/Mica)

Magnetite / Iron Ore

Magnetite (Fe3O4)

Gneiss (Stream-worn Cobble)

Gneiss (Metamorphic rock composed primarily of Quartz, Feldspar, and Mica)

Chert (specifically Chert Nodule/Flint)

Chert (Silicon Dioxide, SiO2)

Gneiss

Gneiss (High-grade metamorphic rock)

Gneiss

Gneiss (High-grade Metamorphic Rock)

Almandine Garnet

Almandine [Fe3Al2(SiO4)3]

Quartz Pebble

Silicon Dioxide (SiO2)

Chert (Jasper/Agate variety)

Silicon Dioxide (SiO2)

Chert (and Chalcedony)

Microcrystalline Quartz (SiO2)

Chert (Yellow or Tan variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety, likely a orthogneiss or paragneiss depending on parent rock)

Granite

Granite (a common rock type, not a single mineral with a formula. Composed primarily of quartz, feldspar, and mica/amphibole).

Jasper (Iron-stained Quartzite/Chert)

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) impurities

Chalcedony (Quartz Nodule)

Silicon Dioxide (SiO2)

Gold Nugget

Native Gold (Au)

Chert Nodule (Commonly known as a Flint or River Cobble)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz Vein in Host Rock (clastic sediment)

Silicon Dioxide (SiO2) in matrix

Turquoise

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

Chalcedony (Agate/Chert variety)

Silicon Dioxide (SiO₂)

Chert (Iron-stained)

Chert (SiO2)

Sandstone (likely Arkosic or Lithic)

Clastic Sedimentary Rock (SiO2 with accessory minerals)

Ferruginous Sandstone

Clastic Sedimentary Rock (Iron-rich)

Chert Pebble

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz (Vein Quartz)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Fossil Rugose Coral (Horn Coral)

Order Rugosa (likely Grewingkia or Heliophyllum species); Calcium Carbonate (CaCO3)

Nuummite

Nuummite (mixture of Anthophyllite and Gedrite)

Gneiss

Gneiss

Greenstone

Metabasalt / Chlorite-Epidote Schist

Gneiss (specifically Banded Gneiss)

Gneiss

Greenstone

Greenschist / Meta-basalt

Gneiss (Cobble)

Gneiss

Banded Gneiss

Gneiss (Metamorphic high-grade, predominantly SiO2, Al2O3, K2O, Na2O)

Lapis Lazuli

Na8(Al6Si6O24)S2 (Lazurite is the primary constituent mineral)

Quartzite

Quartzite (primarily SiO2)

Red Garnet

Almandine and Pyrope (Silicate minerals: Fe3Al2(SiO4)3 and Mg3Al2(SiO4)3)

Gneiss

High-grade regional metamorphic rock (Foliated)

Banded Gneiss

Gneiss (high-grade metamorphic silicate rock)

Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

River Cobble (Salt and Pepper Gneiss)

Gneiss (High-grade regional metamorphic rock)