Antropogenic Rock (Man Made)

Limestone

Calcium Carbonate (CaCO3)

Pink Quartzite

Quartzite (mainly SiO2 with iron oxide impurities)

Sandstone (specifically an Iron-Concretion)

Arenite with Iron Oxide (Limonite/Goethite) cementation

Basalt

Basalt (Composition primarily Plagioclase feldspar, Pyroxene, and Olivine)

Gneiss

Gneiss (High-grade metamorphic rock)

Granite

Phaneritic intrusive igneous rock (composed mainly of Quartz SiO2, Feldspar KAlSi3O8, and Biotite/Mica)

Red Sandstone (Old Red Sandstone)

Ferruginous Sandstone (SiO2 + Fe2O3)

Sandstone (Quartzite-rich River Cobble)

Clastic sedimentary rock (primarily SiO2)

Sandstone (likely with Quartz Veining)

Arenite (primarily SiO2)

Fossilized Coral

Scleractinia (fossil order), primarily Calcium Carbonate (CaCO3)

Granodiorite

Granodiorite (calc-alkaline phaneritic igneous rock)

Basalt Arrowhead (worked stone)

Aphanitic mafic volcanic rock (Basalt)

Quartz with Mica Schist (Pegmatite Specimen)

SiO2 (Silicon Dioxide) and Phyllosilicates (Biotite/Muscovite)

Geode (Chert or Quartz Nodule)

Silicon Dioxide (SiO2)

Druzy Quartz (on Chalcedony/Agate base)

Silicon Dioxide (SiO2)

Pumice

Pumice (Vesicular volcanic glass / Rhyolite or Trachyte)

Schist

Mica Schist

Chert (Nodule)

Silicon dioxide (SiO2) - Cryptocrystalline Quartz

Quartzite

Quartzite (primarily SiO2)

Amethyst

Amethyst (Silicon Dioxide, SiO2)

Quartzite

Quartzite (primarily SiO₂)

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide)

Chert (Jasper/Flint variation)

Chert (SiO2)

Amethyst on Agate/Basalt Matrix

Silicon Dioxide (SiO2) with iron impurities

Sandstone (Greywacke/Siltstone variant)

Clastic Sedimentary Rock (Lithic Wacke)

Quartzite (River Pebble)

Metamorphosed Quartz Sandstone (SiO2)

Quartz Pebble

Quartz (Silicon Dioxide - SiO2)

Crinoid Fossil in Limestone

Class Crinoidea in Carbonate Matrix (CaCO3)

Emerald with Matrix (Emerald in Mica Schist)

Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities

Hag Stone

Siltstone or Fine-grained Sandstone with boring (e.g., Lithophaga impact)

Chert (White Chert/Flint)

Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)

Limonite (Iron Ore)

Limonite; FeO(OH)·nH2O

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Amygdaloidal Basalt

Amygdaloidal Basalt with Secondary Infilling (e.g., Agate, Quartz, or Zeolite)

Turquoise

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

Calcite (Yellow/Orange variety - sometimes called Honey Calcite)

Calcite

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz Vein with Iron Staining

Silicon Dioxide (SiO2) with limonite/hematite staining

Green Moonstone (Garnierite)

Nickel-bearing Magnesium Silicate (often a mix of Serpentine and Talc/Chlorite groups)

Diamond

Diamond (Pure Carbon, C)

Almandine Garnet

Almandine (Fe3Al2Si3O12)

Copper Ore with Chrysocolla and Azurite

Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O (Chrysocolla) / Cu3(CO3)2(OH)2 (Azurite)