Synthetic (Not A Natural Rock)

Travertine

Travertine (CaCO3 - Calcium Carbonate)

Turquoise

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

Chert Nodule (with Ironstone Cortex)

Microcrystalline Silica (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Yellow calcite crystal cluster with calcite fragment

Calcite, calcium carbonate (CaCO₃)

Rock crystal quartz fragment

Quartz (silicon dioxide, SiO₂)

Tumbled and polished quartz crystal points

Quartz (silicon dioxide, SiO₂), chiefly rock crystal with smoky or included varieties

Carnelian Agate

Silicon Dioxide (SiO2) with Iron Oxide impurities

Iron-rich sandstone or lateritic rock

Ferruginous sandstone; predominantly quartz (SiO₂) cemented or stained by iron oxides/hydroxides

White granite

Granite, chiefly quartz–alkali feldspar–plagioclase with biotite/hornblende

Quartzite Pebble (with mineral veining)

Metamorphic Quartzite (SiO2)

Native American Hammerstone / Pitted Stone

Modified lithic artifact (often quartzite, basalt, or granite)

Polished agate/chalcedony fragment

Microcrystalline quartz (SiO₂), likely banded chalcedony or agate

Hag Stone

Sandstone or Limestone with Solution Holes (Bioturbation/Erosion)

Yellow Quartz Pebble

Silicon Dioxide (SiO2)

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Shale or Argillite

Shale (fine-grained clastic sedimentary rock) or Argillite (low-grade metamorphic rock derived from shale)

Gossan (Iron Hat)

Goethite-Hematite rich weathered rock (Fe-hydroxides)

Iron-rich weathered rock (likely limonite/goethite concretion)

Limonite–goethite mixture; chiefly FeO(OH)·nH₂O

Weathered iron-rich rock, likely limonite-bearing sandstone or laterite

Limonite/goethite-rich ferruginous rock; composition commonly FeO(OH)·nH₂O with quartz and clay minerals

Wishing Stone with Quartz Vein

Quartz-veined sedimentary pebble

Black Onyx

Silicon Dioxide (SiO2) with cryptocrystalline structure

Shale with Limonite/Hematite Staining

Argillaceous sedimentary rock with Iron Oxides (FeO(OH)·nH2O / Fe2O3)

Tumbled-looking granite pebble

Granite, chiefly quartz–feldspar with biotite/amphibole

Orange chromium diopside (likely tumbled)

Diopside, CaMgSi₂O₆; orange color may reflect iron-rich composition or surface treatment/inclusion

Quartzite

Quartzite (primarily SiO2)

Vesicular basalt (likely weathered lava rock)

Basalt, predominantly calcium-rich plagioclase, pyroxene, and commonly olivine; vesicular texture from gas bubbles

Granite

Phaneritic plutonic rock (dominated by Quartz, Feldspar, and Mica)

Herkimer Diamond

Quartz (Silicon Dioxide, SiO2)

River Cobble (likely Sandstone or Siltstone type)

Sandstone or Siltstone (common rock types that form river cobbles)

Ironstone (Limonitic Shale)

Ferruginous Siltstone / Goethite-rich Sedimentary Rock

Granite

Phaneritic intrusive igneous rock (Composition: Quartz, Feldspar, Mica)

Carnelian (a variety of Chalcedony)

Silicon Dioxide (SiO2) with iron oxide impurities

Schist (Kyanite Schist)

Kyanite-Mica Schist (primarily Al2SiO5, KAl2(AlSi3O10)(OH)2, and SiO2)

Polished ocean jasper (orbicular jasper), probable

Microcrystalline quartz (SiO₂), chiefly chalcedony with iron-oxide and other mineral inclusions

Basalt Pebble with Quartz Inclusion

Basalt (SiO2 with Fe, Mg silicates) with Quartz (SiO2)

Turquoise

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

Red jasper (iron-rich chalcedony), possibly brecciated

Jasper: microcrystalline quartz, SiO₂, colored mainly by iron oxides/hydroxides

Sandstone with Iron Weathering

Quartz Arenite / Weathered Sandstone

Asphalt Chunk (Bituminous Concrete)

Aggregated Bitumen / Artificial Breccia

Clear Quartz

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)