Anthropogenic (Man Made Material)

Sandstone (Wonderstone)

Clastic Sedimentary Rock (primarily SiO2)

Yellow Quartzite (River Pebble)

Quartzite (primarily Silicon Dioxide, SiO2)

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)

Quartzite Pebble

Quartzite (mostly SiO2)

Sandstone

Arenite

Sandstone (Calcareous Sandstone)

Calcareous Sandstone (primarily SiO2 with CaCO3 cement)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Sandstone (likely Arkose or Quartz Sandstone)

Clastic sedimentary rock (primarily SiO2)

Siltstone Pebble

Siltstone (fine-grained siliciclastic sedimentary rock)

Clear Quartz

Silicon Dioxide (SiO2)

Coquina Limestone

Coquina (Calcium Carbonate, CaCO3)

White seed-bead gemstone strand, likely freshwater pearl or shell pearl

Pearl: nacreous calcium carbonate, chiefly aragonite (CaCO₃) in conchiolin; identification uncertain from image

Tumbled black stone, likely basalt

Basalt; fine-grained plagioclase–pyroxene rock, possibly with magnetite

Amethyst quartz cluster

Quartz, SiO₂; purple coloration from iron impurities and irradiation

Likely quartz-rich mineral fragment

Quartz (SiO₂), possibly iron-stained or included quartz

Geode (Unopened)

Silica-rich Concretion (primarily SiO2)

Textile (Upholstery Fabric)

Woven Polyethylene/Polyester or Cotton Blend

Polished brecciated jasper

Jasper (microcrystalline quartz, SiO₂), likely brecciated and iron-stained

Banded agate (likely carnelian/chalcedony)

Microcrystalline quartz, SiO₂; iron-stained chalcedony

Amygdaloidal basalt (vesicular basalt)

Basalt, commonly containing amygdales of quartz, chalcedony, calcite, or zeolites

Weathered sandstone cobble

Quartz-rich sandstone, primarily SiO₂ with clay/iron-oxide cement

Tumbled blue chalcedony or pale aquamarine-like quartz

Chalcedony (microcrystalline SiO₂), possibly blue quartz; visual identification is uncertain

Emerald

Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)

Quartzite River Pebble

Quartzite (SiO2)

Granite

Felsic intrusive igneous rock

Sandstone

Arenite (primarily SiO2)

Weathered quartz-rich cobble, possibly quartzite or feldspar-rich granite

Quartz–feldspar aggregate; identification is uncertain from the photograph

Smoky quartz (likely)

Quartz, silicon dioxide (SiO₂), naturally irradiated variety

Chert

Microcrystalline Quartz (SiO2)

Granite Cobble

Granite (Phaneritic Igneous Rock)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (varieties including Flint or Jasper)

Microcrystalline Quartz (SiO2)

Chert (variations like Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (Flint)

Chert (SiO2)

Diabase

Diabase (also known as Dolerite)

Chert

Microcrystalline Quartz (SiO2)

Stichtite in Serpentine (Atlantasite)

Mg6Cr2CO3(OH)16·4H2O in Mg3Si2O5(OH)4

Chert

Microcrystalline Quartz (SiO2)

Diamond

Natural Diamond (Carbon, C)

Chert (Flint)

Chert (Silicon Dioxide, SiO2)