Antropogenic (Man Made Glass Byproduct)

Likely polished/tumbled quartz-rich specimen

Quartz, silicon dioxide (SiO₂), possibly an agate or chalcedony variety

Granite

Phaneritic plutonic rock (Quartz, Feldspar, Mica)

Native Silver

Silver (Ag)

Weathered porphyritic volcanic rock

Likely porphyritic andesite or dacite, with plagioclase phenocrysts in a fine-grained volcanic groundmass

Chert (Chert Nodule)

Silicon Dioxide (SiO₂)

Chert (varieties include Flint and Jasper)

Silicon Dioxide (SiO2)

Sandstone (likely Fossilized Wood or Concrete Simulacrum)

Arenite / Silicified Wood / Anthropogenic Concrete

Iron-rich slag or limonite-bearing rock

Hydrated iron oxides, chiefly limonite/goethite (FeO(OH)·nH₂O); possibly industrial iron slag

Quartz

Silicon Dioxide (SiO2)

Pale green tumbled mineral fragment, likely serpentine or green calcite

Probable serpentine-group mineral (Mg3Si2O5(OH)4) or, less likely, calcite (CaCO3); identification is uncertain from the photograph

Polished pink feldspar pebble

Orthoclase or microcline feldspar, KAlSi₃O₈; exact identification is uncertain from the image

Amethyst (Tumbled Cabinet Stone)

Silicon Dioxide (SiO2) with iron impurities

Citrine Geode (or Druzy Citrine)

Silicon Dioxide (SiO₂) - a variety of Quartz

Quartz (Milky Quartz)

Quartz (SiO2 - Silicon Dioxide)

Quartz Vein Quartzite

Metamorphic Quartzite with Quartz Vein (SiO2)

Quartz-bearing iron-rich rock, possibly quartzite or hydrothermal breccia

Quartz (SiO₂) with iron oxides/hydroxides, likely limonite/goethite; exact host rock is uncertain from the photograph

Tumbled amethyst

Amethyst, purple quartz (SiO₂), colored by trace iron and irradiation

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Chert (v. Flint)

Chert (Microcrystalline Quartz, SiO2)

Fulgarite

Fulgurite (Lechatelierite / Vitrified Sand)

Tumbled brown stone, likely smoky quartz or brown jasper

Probable smoky quartz (SiO₂) or iron-rich jasper (microcrystalline SiO₂); image alone is insufficient for certainty

Tumbled white quartz or quartzite pebble

Quartz (SiO₂), possibly massive quartzite

Translucent agate/chalcedony

Microcrystalline quartz (SiO₂), likely chalcedony with agate-like banding

Tumbled blue stone, likely blue aventurine or dyed quartzite

Quartz (SiO₂), likely with inclusions or artificial dye; exact identification requires testing

Agate (or Chalcedony)

SiO2 (Silicon Dioxide) - a cryptocrystalline variety of quartz

Quartz-rich rock, possibly milky quartz or quartzite

Quartz (SiO₂), potentially quartzite if the grainy texture is rock-wide

Indochinite Tektite

Tektite (high-silica impact glass)

Chert (Green Chert or Jasper)

Microcrystalline Quartz (SiO2)

Quartz (likely milky quartz or a stained variety)

Silicon Dioxide (SiO₂)

Tumbled carnelian agate (probable)

Cryptocrystalline quartz, SiO₂; chalcedony variety colored by iron oxides

Snowflake Obsidian

Volcanic glass with Spherulite inclusions (SiO2)

Chert

Chert (Microcrystalline Quartz, SiO2)

Quartz Vein in Host Rock (often Granite or Schist)

Silicon Dioxide (SiO2) within host matrix

Granite pebble

Coarse-grained felsic intrusive igneous rock; mainly quartz, alkali feldspar, plagioclase, and minor biotite or amphibole

Tumbled orange chalcedony (likely carnelian)

Cryptocrystalline quartz, SiO₂; carnelian is orange-red chalcedony colored mainly by iron oxides

Carnelian (red chalcedony)

Chalcedony, microcrystalline quartz (SiO₂), iron-oxide colored variety

Rounded quartz-rich river pebble

Quartz (SiO₂), likely derived from quartzite or granitic rock

Chert Pebble (Jasperoid/Flint)

Silicon Dioxide (SiO2) - cryptocrystalline quartz

Brown quartz-rich stone, possibly smoky quartz or quartzite

Quartz (SiO₂), potentially in a quartzite or silica-rich matrix

Polished black stone, likely black obsidian

Obsidian (volcanic glass), primarily silica-rich rhyolitic composition

Orbicular rhyolite (likely)

Rhyolite, a silica-rich volcanic rock; commonly quartz, alkali feldspar, plagioclase, and iron-rich alteration minerals

Sandstone

Sandstone (lithified arenite/wacke)