Mineral (Man Made Composite)

Opalite (Man-made Glass)

Synthetic Silicon Dioxide Glass (SiO2 + metal oxides)

Terrazzo (Synthetic Composite Rock)

Cementitious or Epoxy Resin-bound Aggregates

Polished brown jasper (likely brecciated or orbicular jasper)

Microcrystalline quartz/chalcedony, SiO₂, with iron-oxide and other mineral inclusions

Black Obsidian

Amorphous volcanic glass (SiO2 + impurities)

Porcelain (White Ceramic)

Mullite-bearing Vitrified Ceramic (Major phases: Mullite Al6Si2O13, Glassy Silica SiO2)

Concrete with Exposed Aggregate

Anthropogenic conglomerate (Concrete)

Green Aventurine

Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)2AlSi3O10(OH)2)

Pyrite Concretion (Grapestone)

Iron Sulfide (FeS2) Concretion

Cubic Zirconia (Simulated Diamond)

Cubic Zirconia (ZrO2)

Blue-dyed tumbled quartz or glass imitation

Quartz (SiO₂), appearance possibly enhanced with blue dye; identity uncertain from image

Sea Glass

Amorphous silicon dioxide (SiO2) - Man-made glass tumbled by nature

Black glassy fragment, likely obsidian or industrial glass

Volcanic glass (obsidian), chiefly amorphous SiO₂; identification uncertain from image

Opalite

Man-made Glass (Synthetic Opalized Glass)

Sea Glass

Man-made silicate glass weathering product

Opalite

Man-made Opalized Glass (Synthetic Glass)

Green Sea Glass

Man-made vitreous material (silica glass)

Milky quartz (likely quartz crystal fragment)

Quartz, silicon dioxide (SiO₂)

Pink Tumbled Quartz (Dyed)

Silicon Dioxide (SiO2)

Dyed Crackle Quartz (Green)

Quenching-treated Quartz (Silicon Dioxide, SiO2)

Iron Slag (Industrial Byproduct)

Anthropogenic Vitrification Product/Ferrous Slag

Goldstone (Brown/Gold variety)

Aventurine Glass (SiO2 with Copper inclusions)

Asphalt (Bituminous pavement)

Bituminous concrete / Asphalt

Sandstone Anvil / Nutting Stone

Quartzose Sandstone (Sedimentary Rock)

Aura Quartz (Titanium/Gold coated)

Silicon Dioxide (SiO2) with metallic vapor deposition

Clear quartz fragment (rock crystal)

Quartz, silicon dioxide (SiO₂)

Polished white calcite sphere (identification tentative)

Calcite, CaCO₃

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Aura Quartz

Titanium/Titanium-Gold treated Silicon Dioxide (SiO2)

Green sea glass or tumbled green quartz (uncertain)

Likely quartz (SiO₂) if natural; alternatively man-made soda-lime glass

Red Slag Glass

Amorphous Silica (Industrial byproduct with metallic oxide dopants)

Green obsidian (likely molded or heat-treated glass-like specimen)

Volcanic glass; predominantly rhyolitic composition (silica-rich amorphous SiO₂)

Green sea glass (likely)

Man-made glass, likely soda-lime silicate glass; not a natural mineral or rock

Sandstone Concretion

Clastic Sedimentary Rock (primarily SiO2 with mineral cement)

Botryoidal chalcedony (likely agate/jasper variety)

Microcrystalline quartz, SiO₂

Polished black pebble, possibly obsidian

Volcanic glass (obsidian), likely; identification is tentative from the image

Baked-clay ceramic fragment (likely brick or pottery)

Fired clay, primarily aluminosilicate minerals; not a natural rock

Blue Goldstone

Goldstone (artificial glass)

Metal Alloy (Likely Pewter or Sterling Silver)

Not a natural geological specimen; composed of refined metals. If pewter, it's a tin-based alloy. If sterling silver, it's 92.5% silver and 7.5% other metals (usually copper).

Sea Glass

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

Polished black stone, likely obsidian

Obsidian (volcanic glass; mostly silica-rich rhyolitic composition)

Blue glassy tumbled stone, likely blue chalcedony or slag glass

Chalcedony (microcrystalline SiO₂), possibly man-made blue glass

Sea Glass

Amorphous Silicon Dioxide (Man-made glass weathered by nature)