Man Made Material (Jewelry, Metal Alloy)

Moldavite

Tektite (Natural Silica Glass)

Moss Agate

Silicon Dioxide (SiO2) with Manganese or Iron Oxide inclusions

Obsidian (Apache Tear)

Amorphous Volcanic Glass (SiO2)

Jasper (Petrified Wood variant)

Silicon Dioxide (SiO2) with iron oxide inclusions

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified Wood (primarily SiO₂)

Chert (Flint)

Silicon Dioxide (SiO2)

Diamond

Carbon (C)

Chert (Flint variety)

Silicon Dioxide (SiO2)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Rough Blue Diamond

Carbon (C)

Diamond (Faceted Gemstone)

Native Carbon (C)

Chert (Beach Pebble)

Microcrystalline Quartz (SiO2)

Polished black-and-white banded stone, likely tourmalinated quartz or zebra jasper

Quartz (SiO₂) with black tourmaline (schorl, NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄), or quartz-rich zebra jasper

Chert (often referred to as 'Jasper' when red)

Chert (microcrystalline quartz, SiO₂)

Chalcedony (specifically Blue Chalcedony or Common Opal variety)

Silicon Dioxide (SiO₂)

Chert (Yellow Jasper)

Microcrystalline Quartz (SiO2)

Tumbled carnelian

Carnelian, a red-orange variety of cryptocrystalline chalcedony (SiO₂)

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified Wood (primarily SiO2)

Diamond

Natural Carbon (C)

Garnet

Garnet group species (likely Almandine, Fe3Al2(SiO4)3)

Petrified Wood

Silicified Wood (primarily Quartz or Chalcedony, SiO2)

Honey calcite (orange calcite)

Calcite — calcium carbonate, CaCO₃

Leopard Skin Jasper

Rhyolite (Silicon Dioxide with impurities), SiO2

Chert (Flint)

Chert (Silicon Dioxide, SiO2)

Weathered gray rock fragment

Likely quartz-rich sandstone or weakly metamorphosed sandstone; exact identification is uncertain from the photograph

Grey Chalcedony (Tumbled)

Chalcedony (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicon Dioxide Fossilized Wood (SiO2)

Carnelian Beads

Silicon Dioxide (Variety of Chalcedony), $SiO_2$

Red Jasper

Microcrystalline Quartz (Chalcedony), SiO2

Mixed Quartz and Jasper Pebbles

Silicon Dioxide (SiO2)

Diamond

Carbon (C)

Chert Pebble

Microcrystalline Quartz (SiO2)

Agate

Silicon dioxide (Chalcedony), SiO2

Dyed Agate

Silicon Dioxide (SiO2) - variety Chalcedony

Chert (Brown Variety)

Microcrystalline quartz (SiO2)

Chert (specifically Flint)

Silicon dioxide (SiO2)

Chert (often called Flint or Jasper)

Chert (Microcrystalline or Cryptocrystalline Silica, SiO2)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)