Industrial Byproduct (Anthropogenic Rock Like Material)

Mica Schist

Schist (Biotite/Muscovite dominant)

Greisen (Quartz-Muscovite-Turretine Rock)

Greisen

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Quartzite (Iron-stained)

Quartzite (SiO2 with Fe-oxides)

Vesicular Basalt

Extrusive Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)

Coarse-grained Granite

Phaneritic Granite (contains Quartz, Feldspar, and Mica)

Coal (likely Bituminous or Lignite)

Organic Sedimentary Rock (Carbonaceous)

Black Tourmaline

Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)

Blue Sapphire

Corundum (Al2O3) with traces of Iron and Titanium

Fossiliferous Limestone (Coquina / Shell Limestone)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Ironstone (possibly Bog Iron or Limonite)

Goethite-rich Ironstone (FeO(OH))

Quartz (Small Fragment)

Silicon Dioxide (SiO2)

Chert Pebble/Nodule

Chert (a microcrystalline or cryptocrystalline sedimentary form of quartz, SiO2)

Tektite (likely Australite)

Tektite (no specific chemical formula as it's a natural glass of variable composition, mostly SiO2, Al2O3, FeO, MgO, CaO, K2O, Na2O, TiO2)

Banded Calcite (often sold as Mexican Onyx or Aragonite)

Calcite/Aragonite (Calcium Carbonate, CaCO3)

Basalt

Basalt

Blue Quartz

Quartz (SiO2) with inclusions

Orange Quartz with Epidote

Silicon Dioxide (SiO2) with Calcium Aluminum Iron Silicate hydroxide (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH))

Basalt (Water-worn Pebble)

Basalt (Mafic volcanic rock)

Anthracite Coal

Anthracite (Carbon-based organic sedimentary rock exposed to metamorphic heat/pressure; Chemical composition is approximately 86%–98% Carbon)

Flint (Chert)

Cryptocrystalline Quartz (SiO2)

Banded Calcite (Cave Onyx)

Calcium Carbonate (CaCO3)

Chert (specifically Flint or Jasper variant)

Microcrystalline quartz (SiO2)

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Matrix

Bituminous Coal

Organic Sedimentary Rock (Carbon-based)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Garnet (likely Pyrope or Almandine)

Garnet Group (complex nesosilicate minerals, e.g., Pyrope Mg3Al2(SiO4)3, Almandine Fe3Al2(SiO4)3, Spessartine Mn3Al2(SiO4)3, Grossular Ca3Al2(SiO4)3, Andradite Ca3Fe2(SiO4)3, Uvarovite Ca3Cr2(SiO4)3). The vivid red color in the image strongly suggests Pyrope or Almandine.

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (specifically Jasper or Flint)

Cryptocrystalline Quartz (SiO2)

Granite

Granite (Phaneritic Igneous Rock)

Limestone with Calcite Crystals

Sedimentary Rock containing Calcium Carbonate (CaCO3)

Quartzite River Rock (with Quartz Vein)

Quartzite (SiO2)

Sand Grain (Silica/Quartz Grain)

Silicon Dioxide (SiO2)

Jasper

Silicon dioxide (SiO2)

Quartz Druzy on Geode Fragment

Silicon Dioxide (SiO2)

Chert (specifically Chalcedony or Flint variation)

Microcrystalline Quartz (SiO2)

Ruby

Corundum (Al2O3)

Chert (Flint variety)

Silicon Dioxide (SiO2)

Quartz (Small Fragment)

Silicon Dioxide (SiO2)

Quartzite

Quartzite (primarily SiO2)

Crushed Limestone

Sedimentary Calcium Carbonate (CaCO3)

Blue Goldstone

Auraventurine (Synthetic glass with cobalt and copper inclusions)