Sedimentary And Metamorphic

Gneiss (specifically a granitic gneiss cobble)

Gneiss (high-grade regional metamorphic rock)

Gneiss (specifically a Granitic Gneiss)

Gneiss (typically composed of Quartz, Feldspar, and Mica/Amphiboles)

Gneiss Pebble

Gneiss

Quartzite

Quartzite (primarily SiO₂)

Petrified Wood

Silicified Wood (primarily Quartz / Chalcedony: SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Gneiss (specifically Biotite Gneiss)

Gneiss (high-grade metamorphic rock primarily composed of Silicates)

White Marble

Recrystallized Calcite (CaCO3)

Anthracite Coal

Anthracite

Aventurine (Green)

Silicon Dioxide (Quartz) with inclusions typically of Fuchsite; SiO2

Quartz

Quartz (SiO₂)

Petrified Wood

Silicified Wood (SiO2)

Biotite Mica

Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)

Quartz Pebble

Silicon Dioxide (SiO2)

Pyrite

Pyrite (Iron sulfide, FeS₂)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Pyrite

Iron Sulfide (FeS2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Pyrite (on a metal substrate)

Iron Sulfide (FeS2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Clear Quartz

Quartz (Silicon Dioxide, SiO2)

Pyrite

Iron Disulfide (FeS2)

Pyrite

Iron Disulfide (FeS2)

Hematite

Iron(III) oxide (Fe2O3)

Petrified Wood

Silicified Wood (primarily SiO₂ - Silicon Dioxide)

Petrified Wood

Silicified Wood (SiO2)

Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Gneiss (specifically a Banded Gneiss pebble)

Gneiss (High-grade Regional Metamorphic Rock)

Granitic Gneiss

Gneiss (high-grade metamorphic rock primarily of quartz, feldspar, and mica)

Fuchsite Quartzite

Fuchsite-bearing Quartzite

Quartz (pebble)

Quartz (SiO₂)

Almandine Garnet

Almandine (Fe3Al2(SiO4)3)

Magnetite / Iron Ore

Magnetite (Fe3O4)

Petrified Wood

Silicified Wood (SiO2)

Quartz (likely Rose Quartz or Milky Quartz based on color)

Quartz (SiO2 - Silicon Dioxide)

Blue Calcite

Calcium Carbonate (CaCO3)

Pyrite (Iron Pyrite)

Iron Sulfide (FeS2)

Calcite

Calcium Carbonate (CaCO3)

Pyrite

Iron Sulfide (FeS2)

Quartz (Smoky/Milky variety)

Silicon Dioxide (SiO2)

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)