Mineral (Synthetic Glass)

Mica Schist or Muscovite

KAl2(AlSi3O10)(OH)2

Polished blue-green glassy slag or coated mineral fragment

Most likely man-made colored glass/slag; exact composition cannot be determined visually

Lepidolite

K(Li,Al)3(Al,Si,4)10(O,F,OH)2

Smoky quartz chips

Quartz, SiO₂ (smoky variety)

Clear quartz crystal (likely quartz fragment)

Quartz, silicon dioxide (SiO₂)

Black Obsidian

Obsidian (Volcanic Glass)

Obsidian (likely)

Volcanic glass, predominantly silica-rich rhyolitic composition (no fixed mineral formula)

Snowflake Obsidian

Volcanic Glass with Spherulite Inclusions (70–75% SiO2)

Potassium Feldspar (Orthoclase / Microcline)

KAlSi3O8 (Potassium Aluminum Silicate)

Ferruginous Quartz

Silicon Dioxide (SiO2) with Iron Oxide (Limonite/Hematite)

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Quartz Geode or Vein Quartz

Silicon Dioxide (SiO2)

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Quartz crystal fragment (likely milky quartz)

Quartz, silicon dioxide (SiO₂), trigonal crystal system

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Tumbled brown quartz (likely smoky quartz)

Quartz, silicon dioxide (SiO₂); brown coloration may be smoky quartz or iron-stained quartz

Quartz with Pyrite and Lichen

Silicon Dioxide (SiO2) with Iron Sulfide (FeS2)

Clear quartz fragment

Quartz (silicon dioxide, SiO₂)

Tumbled pink quartz, possibly rose quartz

Quartz (SiO₂), likely rose quartz; exact identification requires testing

Pumice or Tufa/Travertine

Pumice (if igneous) or Calcareous Tufa (if sedimentary)

Milky quartz with iron-oxide staining

Quartz, silicon dioxide (SiO₂), likely massive or coarsely crystalline; brown areas are limonite/goethite staining

Milky quartz (likely quartz-rich rock)

Quartz, silicon dioxide (SiO₂)

Milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Black tumbled stone, possibly obsidian

Obsidian (volcanic glass; predominantly SiO₂), identification uncertain from image

Quartz (Small Fragment)

Silicon Dioxide (SiO2)

Blue glass-like tumbled specimen

Most likely cobalt-blue slag glass or manufactured glass; not confidently identifiable as a natural mineral from the image

Likely polished/tumbled dark mineral or glassy rock fragment

Indeterminate from image; possibly hornblende, schorl tourmaline, or obsidian

Obsidian

Volcanic Glass

Chert (Flint/Jasper)

Silicon Dioxide (SiO2)

Weathered quartz-rich rock, likely quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with mica or iron-oxide impurities

Green-speckled igneous rock, likely epidote-bearing basalt or serpentinite

Tentatively epidote-bearing basalt (compositionally uncertain from the image)

Black glassy fragment, likely obsidian or industrial glass

Volcanic glass (obsidian), chiefly amorphous SiO₂; identification uncertain from image

Green Glass Cullet / Recycled Glass

Amorphous Silicon Dioxide (SiO2) with various metal oxides

Obsidian

Obsidian (Volcanic Glass)

Tumbled quartz or calcite specimen

Quartz (SiO₂) or calcite (CaCO₃); exact identification requires testing

Amethyst (Raw Quartz)

Silicon Dioxide (SiO2) with iron impurities

Quartz (Tumbled)

Silicon Dioxide (SiO2)

Milky quartz (likely)

Quartz, silicon dioxide (SiO₂)