Glass

Quartzite

Quartzite (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Chert (variations include Flint or Jasper)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Pink quartz (likely rose quartz)

Quartz, silicon dioxide (SiO₂), likely rose quartz; possibly lab-created or treated

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Citrine

Silicon dioxide (SiO2)

Chert Nodules

Microcrystalline Quartz (SiO2)

Snowflake Obsidian

Spherulitic Volcanic Glass (primarily SiO2)

Possible tektite (natural impact glass)

Impact glass; exact type uncertain from photograph (candidate: moldavite or another tektite)

Quartz-rich sandstone or chert fragment

Indeterminate siliciclastic rock; likely quartz arenite or weathered chert

Small metallic-looking mineral/rock fragment

Indeterminate from image; possibly galena, hematite, or metallic slag

Tumbled pink chalcedony (likely rose quartz or pink agate)

Chalcedony, microcrystalline quartz (SiO₂); exact variety is uncertain from the image

Tumbled gray stone, likely quartz-rich pebble

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

Smoky quartz chips

Quartz, SiO₂ (smoky variety)

Tumbled pale blue-green quartz (likely aquamarine-bearing quartz)

Quartz, SiO₂; blue coloration may reflect inclusions or minor iron-bearing minerals

Likely translucent quartz/chalcedony fragment

Silicon dioxide (SiO₂), probably microcrystalline quartz or quartz

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Green Aventurine

Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)

Polished black stone, likely black obsidian

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

Rose Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz (Milky/Clear Quartz)

Silicon Dioxide (SiO2)

Snowflake Obsidian

Obsidian with Cristobalite inclusions (mostly amorphous SiO2)

Green Obsidian Sphere (man-made glass)

Vitreous Silica with Chromium/Iron additives

Likely quartz-rich stone, possibly milky quartz or chalcedony

Quartz (SiO₂), possibly microcrystalline chalcedony

Blue Obsidian

Obsidian

Quartz vein in dark host rock

Quartz (SiO₂), likely within basalt, diabase, or another mafic volcanic rock

Clear quartz crystal (likely quartz point or polished quartz)

Quartz, silicon dioxide (SiO₂)

Amethyst

Purple quartz (SiO₂), colored mainly by iron impurities and irradiation

Tumbled tiger’s-eye

Quartz variety, chiefly fibrous chalcedony pseudomorph after crocidolite; SiO₂

Tumbled amethyst

Quartz, SiO₂; purple variety colored mainly by iron-related defects and irradiation

Polished red jasper or mahogany obsidian (likely jasper)

Microcrystalline quartz, SiO₂, with iron-oxide inclusions

Rose Quartz

Silicon Dioxide (SiO2) with traces of titanium, iron, or manganese

Obsidian (Carved)

Volcanic glass (high-silica amorphous glass, >70% SiO2)

Obsidian (likely black obsidian)

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

Fulgurite

Lechatelierite

Milky quartz fragment

Quartz (silicon dioxide, SiO₂)

Faceted Gemstone

Unknown transparent mineral, possibly Diamond (C), Cubic Zirconia (ZrO2), Quartz (SiO2), or Glass

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

Quartz, silicon dioxide (SiO₂); yellow color likely from iron-related impurities

Aura Quartz (Titanium/Rainbow Quartz)

SiO2 (Silicon Dioxide) with metallic coating