Glass

Rounded gray pebble, likely quartz-rich river cobble

Probable granitic or quartzitic cobble; exact identification requires a fresh surface and tests

Tumbled milky quartz

Quartz (SiO₂), cryptocrystalline-to-massive variety

Milky quartz fragment

Quartz (silicon dioxide, SiO₂)

Likely smoky quartz or quartz-rich tumbled fragment

Quartz, silicon dioxide (SiO₂), possibly smoky quartz

White quartz-rich pebble, possibly chalcedony or milky quartz

Quartz (SiO₂), potentially microcrystalline quartz (chalcedony)

Small brown quartz-rich pebble, possibly chert or jasper

Microcrystalline quartz (SiO₂), tentative

Muscovite Mica

Muscovite - KAl2(AlSi3O10)(F,OH)2

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

Likely quartz-rich stone, possibly milky quartz or chalcedony

Quartz (SiO₂), possibly microcrystalline chalcedony

Amethyst cabochon

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation

Tumbled quartz crystal (likely smoky or iron-stained quartz)

Quartz, silicon dioxide (SiO₂)

Quartz (Milky/Chalcedony variety)

Silicon Dioxide (SiO2)

Tumbled Clear Quartz/Rock Crystal

Silicon Dioxide (SiO2)

Quartz (Variety of Rough Mineral Specimens)

Silicon Dioxide (SiO2)

Quartz (Milky/Common Quartz)

Silicon Dioxide (SiO2)

Black obsidian

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

Pumice

Pumice

Iron-stained quartz-rich rock (likely quartzite or quartz vein material)

Quartz (SiO₂), commonly with limonite/goethite iron oxides; possible quartzite matrix

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

Quartz (Milky or Rough Quartz)

Silicon Dioxide (SiO2)

Tumbled yellow translucent mineral, likely citrine or honey calcite

Citrine: quartz, SiO₂; honey calcite: calcium carbonate, CaCO₃

Beaded gemstone jewelry (likely amethyst, lapis lazuli, and pearl or glass imitation)

Mixed mineral beads; possible quartz (SiO₂) and lazurite-bearing lapis lazuli

Muscovite Mica (Granitic Pegmatite)

Muscovite - KAl2(AlSi3O10)(OH)2

Milky Quartz

Silicon Dioxide (SiO2)

Tumbled amethyst

Quartz, purple variety; silicon dioxide (SiO₂) colored mainly by iron-related defects

Clear quartz crystal

Quartz (silicon dioxide, SiO₂)

Amethyst crystal fragment

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron and irradiation

Smoky quartz crystal

Quartz (silicon dioxide, SiO₂), likely smoky quartz

Weathered quartz-rich rock, likely quartzite

Quartzite (predominantly microcrystalline quartz, SiO₂), possibly quartz-rich sandstone or milky-vein quartz

Weathered quartz-rich rock, possibly milky quartz or quartzite

Quartz (SiO₂), potentially quartzite if metamorphic

Clear Quartz

Silicon Dioxide (SiO2)

Pumice

Pumice (Volcanic Glass)

Obsidian

Obsidian (Volcanic Glass)

Black Obsidian

Obsidian (Volcanic Glass)

Opalite

Synthetic Opalized Glass

Obsidian (Blue)

Volcanic Glass (SiO2)

Obsidian

Obsidian (Volcanic Glass)

Tektite (Indochinite)

Impactite (Natural Glass)

Obsidian

Obsidian (Volcanic Glass)

Obsidian with Perlitic Crust

Volcanic Glass (SiO2)