Biogenic Material

Petrified Wood

Silicified Wood (SiO2 as Quartz/Chert/Chalcedony)

Asphalt (Aggregate)

Bituminous macadam / Concrete Aggregate

Carnelian/chalcedony rough

Microcrystalline quartz (SiO₂), iron-oxide-colored chalcedony

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

Tiger’s-eye fragment

Chatoyant quartz, SiO₂, with pseudomorphic iron-oxide fibers

Quartz-rich pegmatitic rock (likely milky quartz with feldspar and dark mica)

Pegmatite; predominantly quartz (SiO₂), with feldspar and biotite/hornblende

Basaltic Tuff / Volcanic Breccia

Pyroclastic Breccia / Lithic Tuff

River Rock

N/A - Generic term for water-smoothed rock

Quartzite with inclusions

Quartzite

Sandstone

Arenite (primarily Quartz, SiO2)

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

Jadeite (Jade)

NaAlSi2O6 (Sodium Aluminum Silicate)

Petrified Wood

Silicified wood (primarily SiO2 - Silicon Dioxide/Quartz)

Petrified Wood

Silicified Wood (SiO2)

Brecciated jasper with quartz veins

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

Green Glass Cullet / Recycled Glass

Amorphous Silicon Dioxide (SiO2) with various metal oxides

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)

Botryoidal chalcedony (likely white quartz/chalcedony)

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

Asphalt fragment

Bituminous concrete

Rounded weathered pebble

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

Iron-rich weathered rock fragment

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

Sandstone (Ferruginous)

Arenite with Iron Oxide matrix

Brecciated Jasper

SiO2

Petrified Wood

Petrified Wood (Silicified Wood)

Carved Stone Turtle

Carved Soapstone and Quartz

Amethyst (purple quartz)

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

Slag (Industrial Glass Slag)

Amorphous Silicate Glass (often containing Al, Ca, Mg, and Ti oxides)

Sandstone

Arenite