Man Made Glass

Chert (varietal: Flint/Jasper)

Silicon Dioxide (SiO2)

Precious Coral (Red Coral)

Corallium rubrum (Calcium Carbonate, CaCO3)

Blue glassy mineral fragment, possibly sodalite or dyed/cobalt glass

Uncertain; likely sodalite (Na₈Al₆Si₆O₂₄Cl₂) if natural, but vivid blue color may indicate cobalt-colored glass

Chert (Flint)

Silicon Dioxide (SiO2)

Red agate bead (likely dyed or treated)

Agate, a microcrystalline variety of quartz; SiO₂

Black-and-white agate geode pendant

Agate (microcrystalline quartz, SiO₂), likely a hollow geode slice with chalcedony and drusy quartz

Obsidian

Volcanic Glass (SiO2)

Quartzite

Metamorphic Quartzite (SiO2)

Sandstone

Arenite (SiO2, often with CaCO3 or Fe2O3 cement)

Yellow faceted gemstone, likely citrine or synthetic glass

Citrine (quartz, SiO₂) is the leading natural possibility; visual identification is uncertain from the photograph

Chert (likely flint)

Microcrystalline quartz (SiO₂), variety chert; flint is a dark chert variety

Obsidian (Black)

Obsidian (High-silica volcanic glass)

Polished amethyst-bearing quartz

Quartz, SiO₂; purple coloration from irradiation and trace iron

Snowflake Obsidian

Volcanic glass with Cristobalite inclusions (70–75% SiO2)

Chert (Jasper variation)

Microcrystalline Quartz (SiO2)

Polished/tumbled brown-and-white mineral fragment

Indeterminate; possibly quartz-rich jasper, brecciated jasper, or an iron-stained quartz mineral

Quartzite

Metamorphic Rock (Mainly SiO2)

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide)

Quartzite

Metamorphic Quartzite (SiO2)

Chert (Yellow Jasper/Flint)

Silicon Dioxide (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Quartzite

Metamorphic Quartzite (SiO2)

Chert (Jasper/Flint variety)

Silicon Dioxide (SiO2)

Quartzite

Metamorphic Quartzite (SiO2)

Quartzite

Metamorphic Quartzite

Gold ring with a clear faceted gemstone

Likely diamond (carbon, C); the photograph is insufficient to confirm the stone or metal

Quartzite

Metamorphic Quartzite (SiO2)

Quartzite

Metamorphic Quartzite (SiO2)

Goldstone (Red)

Aventurine Glass

Green Quartzite

Metamorphic Quartz Sandstone (SiO2)

Dark quartz point (possibly smoky quartz)

Quartz, SiO₂; the dark color may indicate smoky quartz, but the image is insufficient to confirm

Chert Arrowhead

Chert (Cryptocrystalline variety of Quartz, SiO2)

Sea Glass (Uranium/Vaseline Glass variant)

Silicon Dioxide (SiO2) with trace Uranium Oxide (U3O8)

Asphalt Pavement (with aggregate)

Asphalt concrete

Cardstock (Paper)

Cellulose (C6H10O5)n

Synthetic Resin (Artificial Specimen)

Polyurethane or Polyester Resin

Red cabochon gemstone ring (likely ruby or red spinel; identity unconfirmed)

Possibly corundum (ruby, Al₂O₃) or spinel (MgAl₂O₄); visual identification alone cannot distinguish these from glass or synthetic stones.

Quartz Pebble (Beach Chalcedony)

Silicon Dioxide (SiO2)

Quartzite

Metamorphic Quartzite (SiO2)

Chert

Chert (SiO2)

Chert (often called Flint)

Chert (Cryptocrystalline Quartz, SiO2)

Pale green aventurine (likely quartz) sphere

Quartz, SiO₂; possibly pale green aventurine, with color from inclusions or treatment