Synthetic Polymer (Synthetic Material)

Chert (Quartz Variety)

Silicon Dioxide (SiO2)

Iron-stained quartz-rich rock, possibly jasper/quartzite

Quartz (SiO₂) with iron-oxide staining; likely ferruginous quartzite or jasper

Tumbled chalcedony (likely brown agate/jasper)

Microcrystalline quartz, SiO₂; potentially iron-stained chalcedony or jasper

Tumbled jasper or quartzite pebble

Jasper (microcrystalline quartz, SiO₂), possibly iron-stained quartzite

Carnelian

Chalcedony (cryptocrystalline quartz), SiO2

Asphalt aggregate (crushed stone in bitumen)

Artificial composite; predominantly crushed granite, basalt, limestone, and/or recycled aggregate bound by bitumen

Conical fossil shell or shell fragment

Likely a gastropod shell fragment; exact taxon indeterminate from the image

Tumbled granite or granitic gneiss

Granite, typically quartz + feldspar + mica; possibly foliated granitic gneiss

Mammoth or Mastodon Tooth Fossil

Proboscidea tooth (Mammuthus or Mammut)

Chert (varieties include Flint and Jasper)

Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)

Terrazzo (with Marble and Granite fragments)

Cementitious or resinous composite containing Calcium Carbonate (CaCO3) and Silicates

Lava Rock (Basalt)

Basalt (extrusive igneous rock)

Weathered quartz-rich sandstone or granitic rock

Indeterminate; likely iron-stained quartz sandstone, possibly weathered granite

Tumbled greenstone, likely nephrite jade

Nephrite jade (interlocking tremolite–actinolite amphibole; Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂)

Red Sandstone

Arenite (Ferruginous Sandstone)

Chert or flint with chalcedony/quartz veins

Microcrystalline silica: primarily quartz (SiO₂), including chalcedony; possible fossiliferous limestone or silicified material

Iron-rich quartzite or ironstone

Ferruginous quartzite; predominantly quartz (SiO₂) with hematite/goethite (Fe₂O₃/FeO(OH))

Polished orange agate/jasper cabochon

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide coloration; exact variety uncertain

Quartzite Pebble

Metamorphic Quartzite (SiO2)

Sandstone

Sedimentary Rock (Quartz Arenite)

Sandstone

Sedimentary Rock (Quartz arenite)

Dumortierite Quartz

Dumortierite in Quartz (Al6O3(BO3)(SiO4)3)

Yellow Jasper with Red Inclusion

Silicon Dioxide (SiO2) with Iron Oxides

Amazonite in Quartz

K(AlSi3O8) - Potassium Feldspar with Quartz (SiO2)

River Pebble (Greywacke / Basalt Pebble)

Indeterminate Rounded Pebble (composed of quartz, feldspar, or mafic minerals)

Red Tuff / Sandstone

Rhyolitic Tuff / Pyroclastic Volcanic Rock

Quartz Pebble

Silicon Dioxide (SiO2)

Chalcedony Pebble with Jasper/Iron Oxide Cortex

Silicon Dioxide (SiO2)

Quartz with Iron Staining

Silicon Dioxide (SiO2) with Hematite/Limonite inclusions

Sandstone (Pebble)

Sandstone (SiO2 dominated with minor feldspar/clay)

Unakite

Altered Granite (Unakite)

Sandstone (with Iron Staining)

Quartz Arenite / Ferruginous Sandstone

Epidote (Unakite component) / Green Quartzite

Ca2(Al,Fe)3(SiO4)3(OH)

Unakite

Altered Granite (Epidotized Granite)

Sandstone Pebble

Quartz Arenite / Sandstone

Porphyry

Porphyritic Igneous Rock

Sandstone (Quartzose)

Sandstone (SiO2 dominated)

Quartz Pebble (Iron-stained Chalcedony / Chert)

Silicon Dioxide (SiO2)

Gneiss

Gneiss (Foliated Metamorphic Rock)

Polished green aventurine

Quartzite dominated by quartz (SiO₂), with green fuchsite mica or chlorite inclusions

Rose quartz

Quartz (silicon dioxide, SiO₂), pink variety

Rounded gray pebble

Indeterminate; likely a water-worn silicate or carbonate pebble