Antropogenic (Man Made Glass Byproduct)

Blue Goldstone

Aventurine Glass

Gem-set gold ring

Gold alloy setting with a colorless faceted gemstone, possibly quartz or glass; the stone cannot be identified reliably from the image

Sea Glass (Uranium/Vaseline Glass variant)

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

Tumbled quartzite pebble (likely)

Quartz-rich quartzite; mainly SiO₂

Rough Sapphire (Corundum)

Corundum (Al2O3)

Small metallic-looking mineral/rock fragment

Indeterminate from image; possibly galena, hematite, or metallic slag

Green iridescent glass cabochon or synthetic gemstone

Likely synthetic glass; possibly coated synthetic quartz or lab-created green gemstone

Red jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), colored chiefly by iron oxides

Red gemstone ring, likely garnet or synthetic ruby

Possibly almandine garnet (Fe₃Al₂(SiO₄)₃) or corundum/ruby (Al₂O₃); image alone cannot distinguish

Goldstone (Synthetic Aventurescence Glass)

Cuprous Aventurescent Glass (Silicon Dioxide with Copper inclusions)

Obsidian

Volcanic Glass (Amorphous Silicon Dioxide)

Chert / Jasper

Silicon Dioxide (SiO₂)

Chert (Jasper)

Silicon Dioxide (SiO2)

Chert or Jasper

Microcrystalline Quartz (SiO2)

Flint

SiO2 (Cryptocrystalline Quartz)

Quartzite

Metamorphic Quartz Sandstone

Goldstone

Aventurine Glass (SiO2 + Cu small inclusions)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Goldstone (blue-goldstone–style glass) beads

Artificial aventurine glass, typically silica glass with copper inclusions; not a natural mineral

Obsidian

Volcanic glass

Goldstone (likely blue-free synthetic goldstone pendant)

Synthetic aventurine glass; silica glass with dispersed metallic copper crystals

Chert (Flint / Quartz Nodule)

Microcrystalline Quartz (SiO2)

Yellow faceted gemstone, likely citrine or yellow sapphire

Uncertain; probable quartz (SiO₂) or corundum (Al₂O₃)

Pearl

Biogenic CaCO3 (Aragonite and Calcite)

Blue faceted gemstone, likely synthetic sapphire or blue glass

Corundum (Al₂O₃) if sapphire; identity cannot be confirmed visually

Sea Glass (Kelly Green)

Amorphous Silica (Silicon Dioxide with Iron/Chromium additives)

Blue opalite (often sold as synthetic opal)

Opalite glass; amorphous hydrated silica if natural opal (SiO₂·nH₂O)

Black Chert River Stone

Cryptocrystalline Quartz (SiO2)

Quartzite

Metamorphic Quartzite (SiO2)

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

Probable amber fragment

Amber (fossilized plant resin; chiefly amorphous organic resin, commonly dominated by succinite)

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)