Anthropogenic Material

Asphalt (Aggregate)

Bituminous macadam / Concrete Aggregate

Polished dendritic agate or jasper pebble

Microcrystalline quartz (SiO₂), likely chalcedony with iron-oxide inclusions

Polished amethyst-bearing quartz

Quartz, SiO₂; purple coloration from irradiation and trace iron

Polished tiger’s-eye cabochon (probable)

Quartz variety, SiO₂, with fibrous riebeckite/crocidolite-derived inclusions

Jadeite (Jade)

NaAlSi2O6 (Sodium Aluminum Silicate)

Polished brecciated turquoise-like copper mineral

Likely chrysocolla–malachite–limonite assemblage; possibly turquoise-bearing copper ore

Mica-rich schist (likely biotite schist)

Biotite schist; quartz- and feldspar-bearing, with abundant mica

Foliated metamorphic rock, likely gneiss or schist

Quartz–feldspar–mica gneiss/schist; exact identification requires petrographic examination

Red corundum (ruby rough)

Corundum, aluminum oxide (Al₂O₃); ruby is chromium-bearing red corundum

Likely serpentinized ultramafic rock (serpentinite)

Serpentinite; chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with possible olivine, pyroxene, magnetite, and talc

Likely quartz-rich metamorphic rock (quartzite)

Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with mica or feldspar

Tumbled greenstone (likely serpentine or nephrite jade)

Serpentine-group minerals, commonly antigorite; possibly nephrite, a fibrous aggregate of amphibole (actinolite–tremolite)

Rounded river pebble, likely quartz-rich sandstone or weathered quartzite

Indeterminate; probable quartz (SiO₂)-rich clastic rock

Amazonite (green microcline feldspar)

Microcline, KAlSi₃O₈

Vesicular basalt (scoriaceous volcanic rock)

Basalt, chiefly plagioclase, pyroxene, and commonly olivine; vesicles may be lined with secondary minerals

Milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Quartzite

Quartz-rich metamorphic rock; chiefly SiO₂

Biotite schist (likely graphite-bearing)

Mica schist; chiefly quartz + biotite mica, with possible graphite and feldspar

Limestone

Sedimentary rock composed mainly of calcium carbonate (CaCO3)

Coquina / Limonite-stained Limestone

Sedimentary Limestone with Iron Oxyhydroxide (FeO(OH)·nH2O)

Rounded weathered pebble

Likely fine-grained sandstone, siltstone, or weathered volcanic rock; exact identification is uncertain from the image

Sandstone

Arenite

Granite

Granite

Petrified Wood

Silicified Wood (SiO2 as Quartz/Chert/Chalcedony)

Petrified Wood

Silicified wood (primarily SiO2 - Silicon Dioxide/Quartz)

Petrified Wood

Silicified Wood (SiO2)

Red agate bead (likely dyed or treated)

Agate, a microcrystalline variety of quartz; SiO₂

Amethyst (purple quartz)

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

Yellow-brown jasper or silicified volcanic rock

Microcrystalline quartz (chalcedony), SiO₂, likely jasper

Gold-bearing quartz or ironstone fragment

Quartz (SiO₂) with possible native gold and iron oxides

Polished Ocean Jasper beads

Orbicular jasper (microcrystalline quartz, SiO₂), commonly sold as ocean jasper

Weathered gray sandstone or fine-grained metamorphic rock

Likely quartz-rich sandstone (quartz arenite), possibly weakly metamorphosed metasandstone

Iron-rich weathered rock fragment

Indeterminate; likely limonite/goethite-bearing sandstone or lateritic ironstone

Green Glass Cullet / Recycled Glass

Amorphous Silicon Dioxide (SiO2) with various metal oxides

Sandstone (Ferruginous)

Arenite with Iron Oxide matrix

Petrified Wood

Petrified Wood (Silicified Wood)

Slag (Industrial Byproduct)

Ferro-silicate glass (Slag)

Green Sea Glass

Amorphous Silica (man-made glass), SiO2 + additive metal oxides

Goldfish Cracker (Culinary Mimic)

Cibus aurum (Commonly composed of Enriched Wheat Flour and Cheddar Cheese)

Sea Glass (Uranium/Vaseline Glass variant)

Silicon Dioxide (SiO2) with trace Uranium Oxide (U3O8)

Brecciated jasper with quartz veins

Silica-rich breccia; predominantly microcrystalline quartz/chalcedony (SiO₂) with iron-oxide staining

Botryoidal chalcedony (likely white quartz/chalcedony)

Microcrystalline quartz, SiO₂; possibly partly altered carbonate or opaline silica