Mineral Like (Natural Glass)

Tektite (Indochinite)

Tektite (Lechatelierite-rich silica glass)

Conglomerate

Clastic sedimentary rock (Puddingstone)

Dyed or synthetic turquoise-blue glass-like specimen

Likely man-made colored glass or resin; exact identification requires testing

Blue goldstone (man-made glass)

Copper-bearing aventurine glass; synthetic silicate glass

Opalite

Synthetic Opalite Glass / Opalized Glass

Green sea glass (likely bottle glass)

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

Sandstone

Sedimentary Clastic Rock

Green Obsidian Sphere (man-made glass)

Vitreous Silica with Chromium/Iron additives

Blue Sapphire (likely costume glass imitation)

Corundum (Al2O3) with iron/titanium impurities

Possible tektite or iron-rich slag-like natural specimen

Uncertain; possibly natural glass (tektite) or magnetite-rich rock

Sandstone

Clastic sedimentary rock (primarily SiO2)

Sandstone

Arenite (SiO2 based)

Sandstone

Arenite (SiO2 primarily)

Raw Citrine Quartz

Silicon Dioxide (SiO2)

Red heart-shaped glass bead in a wire-wrapped jewelry charm

Likely colored glass (amorphous silica-based material); the image does not show an identifiable geological specimen

Sandstone

Arenite (SiO2 based typically)

Obsidian

Volcanic Glass (Silica-rich glass)

Citrine Quartz

Silicon Dioxide (SiO2) with trace Iron impurities

Blue Glass / Slag Glass

Amorphous silicon dioxide (SiO2) with cobalt colorants

Opalite

Synthetic Silicon Dioxide (SiO2)

Black obsidian (likely)

Volcanic glass, chiefly silica-rich rhyolitic composition (SiO₂-rich); exact identification cannot be confirmed from the image

Blue Obsidian (Cullet Glass)

Silicon Dioxide (Amorphous Glass)

Sandstone

Arenite

Opalite (Man-made Glass)

Synthetic Opalised Glass

Sandstone

Clastic sedimentary rock composed mainly of quartz and feldspar

Opalite

Synthesized glass / Silicon dioxide glass

Prasiolite (Green Quartz) / Sea Glass Amalgam

SiO2 (Silicon Dioxide)

Opalite (likely man-made glass)

Opalite; amorphous silica glass, not a natural mineral

Tumbled amethyst (likely)

Quartz, SiO₂; purple variety known as amethyst

Sandstone (Ferruginous)

Arenite (SiO2 with Fe2O3 cement)

Opalite (Synthetic Opalized Glass)

Synthetic Silicon Dioxide (SiO2) glass

Opalite

Synthetic glass / Simulated opal

Sandstone

Sandstone (Sedimentary rock composed of silicate grains)

Opalite

Synthetic Opalized Glass / Man-made Glass

Quartz (Smoky/Brown variety)

Silicon dioxide (SiO2)

Green glass-like cabochon, likely synthetic glass or resin

Unidentified green transparent material; possibly molded glass, synthetic spinel, or resin

Sandstone

Arenite (Clastic Sedimentary Rock)

Yellow Quartz (or Citrine Quartz)

Silicon Dioxide (SiO2)

Tektite (Indochinite)

Tektite (Natural silica glass)

Sandstone

Sandstone (SiO2-rich detrital sedimentary rock)

Goldstone

Avventurina (Cu + SiO2 glass)

Smoky Quartz

Silicon Dioxide (SiO2) with aluminum impurities