Anthropogenic Specimen (Man Made Material)

Pyrite Concretion (Grapestone)

Iron Sulfide (FeS2) Concretion

Opalite (a synthetic glass, often confused with Opal)

Silicon dioxide glass (SiO2nH2O, for natural opal)

Sandstone Anvil / Nutting Stone

Quartzose Sandstone (Sedimentary Rock)

Dyed Crackle Quartz (Green)

Quenching-treated Quartz (Silicon Dioxide, SiO2)

Quartzite (Engineered Stone)

Silicon Dioxide (SiO2) based synthetic composite

Sandstone Concretion

Clastic Sedimentary Rock (primarily SiO2 with mineral cement)

Slag

Anthropogenic Vitrophyre (Iron or Smelting Slag)

Opalite

Synthetic Glass, SiO2 base with metallic inclusions

Goldstone (Brown/Gold variety)

Aventurine Glass (SiO2 with Copper inclusions)

Blue Goldstone

Goldstone (artificial glass)

Carved labradorite fish

Labradorite, calcium-rich plagioclase feldspar (approximately (Ca,Na)(Al,Si)₄O₈)

Limpets Shell / Fossil Specimen

Patellogastropoda (Class)

Black Obsidian

Amorphous volcanic glass (SiO2 + impurities)

Aura Quartz (Titanium/Gold coated)

Silicon Dioxide (SiO2) with metallic vapor deposition

Malachite

Malachite, Cu₂CO₃(OH)₂; a banded botryoidal copper carbonate specimen

Man-made Jewelry (Metal and Glass/Plastic)

Synthetic Alloy and Amorphous Solid (SiO2/Polymer)

Likely weathered metallic mineral or slag fragment

Uncertain; possibly limonite/goethite-coated iron mineral, or industrial iron slag

Diamond

Carbon (C)

Green glass cabochon or tumbled stone

Indeterminate; likely man-made glass, possibly aventurine glass rather than a natural mineral

Aura Quartz

Titanium/Titanium-Gold treated Silicon Dioxide (SiO2)

Red Slag Glass

Amorphous Silica (Industrial byproduct with metallic oxide dopants)

Chert (Arrowhead Fragment)

Silicon Dioxide (SiO2)

Cullet Glass (sometimes mistaken for Blue Obsidian or Slag)

Amorphous Silicon Dioxide (SiO2) with chemical additives (e.g., Cobalt for blue color)

Chert Nodule

Microcrystalline Quartz (SiO2)

Polished silver sheen obsidian heart

Obsidian (volcanic glass), primarily rhyolitic silica-rich glass

Diamond (as set in a gold ring)

Carbon (C)

Sandstone Concretion

Clastic sedimentary rock (primarily Quartz SiO2)

Fossilized gastropod (likely nerite or related sea snail)

Gastropoda; shell composed originally of aragonite/calcite, commonly replaced or infilled by calcite

Chert

Microcrystalline Quartz (SiO2)

Trilobite fossil

Trilobita (exact species indeterminable from the image)

Slag

Ferrous Slag (Siliceous industrial waste)

Conglomerate

Conglomerate Rock (Paraconglomerate)

Green Aventurine

Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)

Chert

Microcrystalline Quartz (SiO2)

Sea Glass

Amorphous silicon dioxide (Man-made glass weathered by nature)

Yellow faceted gemstone, likely citrine or synthetic glass

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

Asphalt (Bituminous Concrete)

Bituminous Concrete / Pavement

Yellow cabochon gemstone, likely citrine or yellow glass imitation

Quartz (SiO₂), if natural citrine; visual evidence is insufficient to exclude man-made glass or resin

Polished blue chalcedony (possibly agate)

Microcrystalline quartz, SiO₂; chalcedony, potentially banded agate

Blue goldstone beads

Man-made aventurine glass (silica glass with metallic copper inclusions), not natural lapis lazuli

Green glass sphere/marble

Soda-lime glass (primarily SiO2, Na2O, CaO)

Chert (specifically a Lithic Flake)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz