Not A Rock (Man Made Origin)

Vesicular basalt (probable iron-rich volcanic rock)

Basalt; chiefly plagioclase, clinopyroxene, olivine, and Fe-Ti oxides

Opalite

Synthetic Opalite (Man-made glass)

Cullet Glass (Slag)

Amorphous Silicon Dioxide (Man-made)

Green Sea Glass

Man-made silicate glass (weathered)

Crushed Stone (Likely Limestone or Granite)

Calcium Carbonate (CaCO3) for Limestone / Quartz and Feldspar for Granite

Asphalt (Bituminous Concrete)

Bituminous mix containing aggregates and petroleum-based binder (CnH2n+2)

Opalite (Man-made Glass)

Fused glass (typically made of dolomite and metal opacifiers)

Man-made earbud charging case (Not a rock or mineral)

Acrylonitrile Butadiene Styrene (ABS) Plastic with electronic components

Baked-clay ceramic fragment (likely brick or pottery)

Fired clay, primarily aluminosilicate minerals; not a natural rock

Slag

Ferrous Slag (Amorphous calcium-magnesium-aluminum silicates)

Chert Arrowhead (Projectile Point)

Microcrystalline Quartz (Chert or Flint)

Sandstone Concretion

Clastic sedimentary rock (primarily Quartz SiO2)

Sandstone Concretion

Clastic Sedimentary Rock (primarily SiO2 with mineral cement)

Titanium-coated Metal Cube (Man-made Fidget Toy)

Titanium-anodized or electroplated alloy (e.g., Ti-coated Zinc or Aluminum)

Slag (Industrial Glass/Glassy Rock)

Anthropogenic Vitreous Material

Green sea glass (likely bottle glass)

Man-made soda–lime silicate glass; not a natural mineral

Green sea glass (likely bottle glass)

Man-made soda-lime silicate glass; not a natural mineral

Green sea glass (likely)

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

Opalite

Synthetic Glass (Silica-based)

Costume Jewelry with Synthetic Gemstones

Synthetic Cubic Zirconia and Glass (SiO2 / ZrO2)

Asphalt Concrete

Bituminous Concrete

Opaline Glass (Opalite)

Synthetic Silicon Dioxide Glass

Titanium Aura Quartz

Titanium bonded Silicon Dioxide (SiO2 + Ti)

Chert Concretion (with typical hematite/limonite staining)

Sedimentary Concretion (SiO2 with FeO(OH)⋅nH2O)

Rounded granite cobble

Granite, a coarse-grained felsic intrusive igneous rock composed chiefly of quartz, feldspar, and mica

Clear quartz fragment (rock crystal)

Quartz, silicon dioxide (SiO₂)

Blue Goldstone

Auraventurine (Synthetic glass with cobalt and copper inclusions)

Aura Quartz (Titanium Quartz)

Titanium-coated Silicon Dioxide (SiO2 + Ti)

Concrete

Anthropogenic Sedimentary Conglomerate (Cement mixture: typically Ca2SiO4, Ca3SiO5, Ca3Al2O6)

Red Slag Glass

Amorphous Silica (Industrial byproduct with metallic oxide dopants)

Polished obsidian

Volcanic glass; predominantly rhyolitic SiO₂

Opalite

Synthetic Glass (Amorphized Silicon Dioxide)

Opalite

Synthetic Glass (Simulated Opal)

Opalite

Synthetic Glass (Simulated Opal)

Synthetic Resin / Plastic Figurine

Synthetic Polymer (Copolymer of Polyethylene or Resin)

Aura Quartz

Titanium or Gold bonded Silicon Dioxide (SiO2)

Blue Obsidian

Volcanic Glass (SiO2 with inclusions)

Green glass sphere/marble

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

Dalmatian jasper

Porphyritic microcrystalline quartz-rich rock, commonly sold as Dalmatian jasper; spots are chiefly arfvedsonite/amphibole minerals, sometimes altered feldspar

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).

Blue Obsidian (Cullet Glass)

Silicon Dioxide (Amorphous Glass)

Goldstone (Red/Brown)

Aventurine Glass (SiO2 with Copper inclusions)