Antropogenic (Man Made Glass Byproduct)

Green Obsidian Slag Glass

Silicon Dioxide (Amorphous Glass)

Opalite (Man-made Glass)

Fused glass (typically made of dolomite and metal opacifiers)

Blue Glass or Slag Glass

Amorphous Silica (Anthropogenic Glass)

Quartz (likely milky quartz or quartz glass-like fragment)

Quartz, silicon dioxide (SiO₂)

Libyan Desert Glass

Tektite (high-silica impact glass), SiO2

White sea glass (naturally frosted glass fragment)

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

Tumbled opalite (likely man-made glass)

Opalite, a trade name for opalescent glass; not natural opal

Opalite

Synthetically produced glass (Silicon Dioxide with metallic inclusions)

Smelter Slag

Anthropogenic Silicate Slag

Black tumbled stone, possibly obsidian

Obsidian (volcanic glass; predominantly SiO₂), identification uncertain from image

Clear quartz sphere

Quartz (silicon dioxide, SiO₂)

Libyan Desert Glass

Libyan Desert Glass (SiO2 with trace elements)

Sea Glass (White/Clear)

Amorphous Silica (Alkali-Lime-Silica Glass), SiO2 + Na2O + CaO

Chert (Arrowheads)

Microcrystalline Quartz (SiO2)

Tumbled clear quartz (rock crystal)

Quartz, silicon dioxide (SiO₂)

Carborundum (Silicon Carbide)

Silicon carbide (SiC)

Tumbled milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Clear quartz tumbled stone

Quartz (silicon dioxide, SiO₂)

Obsidian (Blue)

Volcanic Glass (SiO2)

Asphalt Concrete (Bituminous Conglomerate)

Anthropogenic Bituminous Conglomerate

Opalite

Synthetic Opalised Glass

Strawberry Quartz

Silicon Dioxide (SiO2) with Hematite or Goethite inclusions

Blue glassy gemstone cabochon, likely dyed chalcedony or glass

Uncertain; possible dyed chalcedony (microcrystalline quartz, SiO₂)

Blue cabochon gemstone, likely synthetic glass or dyed stone

Indeterminate from image; possible glass, synthetic spinel, sodalite, or lapis lazuli

Concrete Rubble with Aggregate

Hardened Portland Cement Paste with Coarse Aggregate

Blue Goldstone

Man-made glass with suspended copper, cobalt, or manganese particles

Green sea glass or tumbled green quartz (uncertain)

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

Opalite

Synthetic Opalized Glass

Clear quartz fragment (rock crystal)

Quartz, silicon dioxide (SiO₂)

Exposed Aggregate Concrete (Pea Gravel)

Concrete with Siliceous Alluvial Gravels

Moldavite

Tektite (Impact Glass), ~80% SiO2 + Al2O3

Tumbled gray stone, likely quartz-rich pebble

Probable microcrystalline quartz/chalcedony (SiO₂), possibly gray jasper or quartzite

Opalite (likely man-made opalescent glass)

Opalite; not a true mineral, typically synthetic opalescent glass (silica-based)

Likely clear quartz pebble or glassy quartz fragment

Quartz (silicon dioxide, SiO₂)

Green sea glass (likely bottle glass)

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

Concrete Fragment

Hardened Portland cement and mineral aggregate

Black glassy fragment, likely obsidian or industrial glass

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

Decorative mosaic cross containing mixed rock and glass fragments

Polychrome aggregate; likely quartz, feldspar, marble, granite, and assorted colored glass

Opalite

Synthetic Glass (Simulated Moonstone/Opal)

Blue Goldstone

Aventurine Glass

Rock crystal (clear quartz), possibly cloudy quartz

Quartz, silicon dioxide (SiO₂)

Asphalt Concrete

Bituminous conglomerate