Tektite (Natural Glass)

Pumice

Pumice (volcanic glass)

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

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

Red Jasper (with Quartz and Chert)

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Citrine (Heat-treated Amethyst)

Citrine Quartz (SiO2)

Cullet Glass (sometimes mistaken for Blue Obsidian or Slag)

Amorphous Silicon Dioxide (SiO2) with chemical additives (e.g., Cobalt for blue color)

Opalite

Synthetic glass (SiO2 + impurities)

Quartzite (or Engineered Quartz Stone)

SiO2 (Silicon Dioxide)

Opalite

Synthetic Opalite Glass

Blue Quartz / Glass Gemstone Pendant

SiO2 (Silicon Dioxide) or Synthetic Glass

Obsidian

Obsidian (principally SiO2 - Silicon Dioxide)

Red gemstone ring, possibly synthetic ruby or red glass

Unidentified red stone; ruby is corundum (Al₂O₃), but the image cannot confirm its identity

Likely polished black stone, possibly obsidian

Obsidian (volcanic glass; primarily SiO₂), tentative identification

Polished black obsidian

Volcanic glass; primarily silica-rich rhyolitic composition (SiO₂)

Iron-stained quartz-rich rock, likely granite or pegmatite fragment

Weathered granite/pegmatite; mainly quartz (SiO₂) with feldspar and iron-oxide staining

Obsidian (black volcanic glass)

Obsidian; predominantly rhyolitic volcanic glass, mainly SiO₂ with minor feldspar, quartz, and iron oxides

Citrine Quartz

Silicon Dioxide (SiO2) with iron impurities

Sea Glass

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

Opalite

Synthetic Glass, SiO2 base with metallic inclusions

Sandstone (likely Arkosic)

Clastic Sedimentary Rock (primarily SiO2 with Feldspar)

Blue glassy gemstone cabochon, likely dyed chalcedony or glass

Uncertain; possible dyed chalcedony (microcrystalline quartz, SiO₂)

Blue Agate (Dyed)

Silicon Dioxide (SiO2)

Quartz (Pebble)

Silicon Dioxide (SiO2)

Diamond / Clear Quartz / Glass paste

Carbon (Diamond) / Silicon Dioxide (Quartz)

Cullet (Slag Glass)

Amorphous Silica (Industrial byproduct)

Tumbled agate beads

Agate, a banded microcrystalline variety of chalcedony (SiO₂)

Weathered, iron-stained quartz-rich rock

Likely quartzite or massive quartz (SiO₂), possibly with limonite/goethite staining

Red-orange cabochon, likely carnelian or glass imitation

Carnelian: chalcedony (microcrystalline SiO₂), commonly iron-colored

Red glassy cabochon, likely synthetic ruby or red glass

Uncertain; possible synthetic corundum (Al₂O₃, chromium-colored) or man-made glass

Tumbled citrine or yellow quartz

Quartz, silicon dioxide (SiO₂); likely iron-colored or heat-treated citrine

Obsidian

Volcanic Glass

Obsidian

Volcanic glass

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Blue glass-like cabochon, likely dyed or synthetic material

Uncertain; possibly dyed chalcedony, synthetic spinel, or blue glass

Blue glassy tumbled stone, likely blue chalcedony or slag glass

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

Diamond (or Simulant)

Carbon (C)

Green Sea Glass

Man-made vitreous material (silica glass)

Tumbled yellow quartz (likely citrine or iron-stained quartz)

Quartz, silicon dioxide (SiO₂), yellow coloration from iron impurities

Blue Sapphire

Corundum (Al2O3)

Orange Quartz (Citrine Quartz)

Silicon Dioxide (SiO2) with iron impurities

Tumbled pink quartz (likely rose quartz)

Rose quartz, quartz (SiO₂), commonly colored by trace elements and microscopic inclusions

Clear Quartz (Cut/Faceted Gemstone)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)