Rock (Likely Sedimentary)

Chert Fossil (Pebble)

Microcrystalline Quartz (SiO2) with biogenic inclusions

Honey calcite crystal cluster

Calcite (calcium carbonate, CaCO₃)

Vesicular basalt (likely scoria)

Mafic volcanic rock; predominantly plagioclase, pyroxene, and volcanic glass, with possible olivine

Polished black stone pendant, likely obsidian

Volcanic glass; primarily silica-rich rhyolitic glass (SiO₂), if obsidian

Mosasaur Tooth

Mosasauridae (likely Prognathodon or Mosasaurus species)

Chert Nodules in Sedimentary Rock

Microcrystalline Quartz (SiO2) within Clastic Matrix

Tumbled honey calcite (likely aragonite/calcite material)

Calcite, CaCO₃; possibly aragonite, a polymorph of CaCO₃

Quartz Pebble

Silicon Dioxide (SiO2)

Calcite with iron staining

Calcium Carbonate (CaCO3)

Weathered granitic rock

Granite or granodiorite, likely quartz–feldspar–mica aggregate

Granite (likely weathered quartz-bearing granite)

Granite; primarily quartz, feldspar, and mica/amphibole

Sandstone Pebble / Quartzite Pebble

SiO2 (Silicon Dioxide enriched sedimentary rock)

Weathered vesicular stone, possibly pumice or scoria

Vesicular volcanic rock; likely pumice (highly vesicular rhyolitic material) or scoria (basaltic material)

Flint (chert), possibly fossil-bearing

Microcrystalline quartz (SiO₂), chalcedony/flint variety

Trilobite Fossil in Limestone

Trilobita (Class), likely embedded in fossiliferous limestone (CaCO3)

Chert / Flint Arrowheads

Cryptocrystalline Quartz (SiO2)

Granite Pebble (Pink Granite)

Phaneritic Igneous Rock (primarily Quartz, Potassium Feldspar, and Plagioclase)

Tumbled blue-green chrysocolla (likely chrysocolla with quartz)

Chrysocolla, hydrated copper aluminum silicate; commonly intergrown with quartz, Cu₂H₂Si₂O₅(OH)₄

Chalcedony (likely agate/chert fragment)

Microcrystalline quartz, SiO₂

Polished carnelian-rich agate (likely polyhedral jasper/chalcedony)

Microcrystalline quartz, SiO₂, with iron-oxide inclusions

Sandstone

Arenite

Sandstone

Arenite (SiO2 predominantly)

Tumbled dark stone, likely basalt or basaltic pebble

Fine-grained mafic volcanic rock; commonly composed of plagioclase, pyroxene, and minor olivine (basalt)

Yellow Quartz Pebble

Silicon Dioxide (SiO2)

Banded Chert

Microcrystalline Quartz (SiO2)

Chert (Nodule)

Silicon Dioxide (SiO2)

Quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂)

Scoria (with likely iron oxidation)

Scoria (Basaltic Scoria)

Quartz Pebble

Silicon Dioxide (SiO2)

Carved Sea Turtle Figurine (Aventurine / Quartz / Jasper)

Quartz variety (SiO2) / Polycrystalline Quartz Aggregate

Weathered porphyritic volcanic rock

Likely porphyritic andesite or dacite, with plagioclase phenocrysts in a fine-grained volcanic groundmass

Druzy Quartz on Matrix

Silicon Dioxide (SiO2)

Pink Garnet (likely Almandine or Rhodolite)

Garnet Group (Fe3Al2(SiO4)3 to Mg3Al2(SiO4)3)

Rounded dark river pebble, likely basalt

Basalt; fine-grained mafic volcanic rock, typically plagioclase + pyroxene ± olivine

Quartz Geode

Silicon Dioxide (SiO2)

Tumbled yellow calcite

Calcite (calcium carbonate, CaCO₃)

Quartzite River Stone

Metamorphosed Quartz-rich Sandstone (SiO2)

Weathered gray granitic rock

Granite, likely quartz–feldspar–mica aggregate

Quartz-rich pegmatite or quartz vein rock

Mostly quartz (SiO₂), with probable feldspar and iron-oxide staining

Devil's Toenail

Gryphaea (extinct genus of foam oysters, typically composed of Calcite CaCO3)

Quartz Vein in Siltstone

Siltstone with Quartz (SiO2) inclusion

Tumbled blue stone, likely blue aventurine or dyed quartzite

Quartz (SiO₂), likely with inclusions or artificial dye; exact identification requires testing