Tektite (Natural Glass)

Likely yellow quartz gemstone ring

Quartz (SiO₂), possibly heat-treated citrine or lemon quartz; metal setting appears to be brass/gold-colored alloy

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

Smoky Quartz

Silicon Dioxide (SiO2)

Blue Goldstone

Aventurine Glass (SiO2 with Cobalt/Copper inclusions)

Tumbled emerald chips

Emerald, green beryl (Be₃Al₂Si₆O₁₈), colored mainly by chromium and/or vanadium

Cut diamond-like gemstone

Likely cubic zirconia (zirconium dioxide, ZrO₂) or glass; natural diamond (carbon, C) cannot be confirmed from an image

Likely quartz fragment

Quartz (silicon dioxide, SiO₂)

Green Aventurine

Silicon Dioxide (SiO2) with Fuchsite inclusions (Quartzite)

Quartz with Iron Inclusions

Silicon Dioxide (SiO2) with Hematite or Limonite staining

Dyed Quartz Geode

Dyed crystalline quartz (Silicon Dioxide, SiO2)

Mahogany Obsidian

Volcanic Glass with Hematite inclusions (SiO2)

Snowflake obsidian

Volcanic glass (silica-rich rhyolitic composition), commonly with cristobalite inclusions

Blue faceted gemstone, likely synthetic sapphire or blue glass

Corundum (Al₂O₃) if sapphire; identity cannot be confirmed visually

Sandstone

Sedimentary quartz arenite

Quartzite Pebble

Quartzite (primarily SiO2)

Sandstone (Pebble)

Arenite (primarily SiO2)

Sandstone

Arenite (SiO2 primarily)

Sandstone

Arenite (primarily SiO2)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Sandstone

Arenite (variable SiO2 composition)

Sandstone (Ferruginous)

Sandstone (Clastic sedimentary rock, predominantly SiO2 with Fe2O3 cement)

Sandstone (Quartzose Sandstone)

Clastic sedimentary rock (primarily SiO2)

Amethyst

Amethyst (Silicon Dioxide, SiO2 + Fe4+)

Smoky Quartz

Silicon Dioxide (SiO2)

Tumbled quartz-rich pebble

Quartz (SiO₂), possibly iron-stained or included quartz

Tumbled chalcedony or agate pebble

Microcrystalline quartz (SiO₂), likely chalcedony with possible iron-oxide inclusions

Snowflake Obsidian

Volcanic Glass (SiO2 rich with Cristobalite inclusions)

Polished black obsidian (probable)

Volcanic glass; predominantly rhyolitic silica glass (approximately 70–80% SiO₂)

Green Glass Cullet / Recycled Glass

Amorphous Silicon Dioxide (SiO2) with various metal oxides

Smoky Quartz

Silicon Dioxide (SiO2)

Smoky Quartz (with Iron Oxidation)

Silicon Dioxide (SiO2)

Weathered brown stone, possibly chert or iron-stained limestone

Uncertain; likely microcrystalline quartz (SiO₂) chert or calcitic limestone (CaCO₃)

Gemstone bead necklace, likely mixed tourmaline and quartz

Probable schorl/dravite tourmaline with quartz or smoky quartz; exact identification requires testing

Sandstone

Arenite

Opalite

Synthetic Glass (Simulated Moonstone/Opal)

Smoky Quartz

Silicon Dioxide (SiO2)

Polished black stone, likely black obsidian

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

Yellow quartz crystal (likely citrine or iron-stained quartz)

Quartz, silicon dioxide (SiO₂)

Faceted yellow-brown gemstone ring, possibly citrine

Unidentified faceted gem; citrine is quartz (SiO₂), but the photo is insufficient for a reliable identification

Polished obsidian

Volcanic glass, primarily silica-rich rhyolitic composition (approximately 70–75% SiO₂)

Green Aventurine (or Green Quartz)

Silicon Dioxide (SiO2) with inclusions of Fuchsite

Green Aventurine

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