Organic Material (Likely A Fruit Or Berry)

Chert (Flint)

Silicon dioxide (SiO2) - Cryptocrystalline Quartz

Honey/brown agate (chalcedony)

Microcrystalline quartz, SiO₂; likely translucent agate or chalcedony

Blue topaz (likely treated)

Topaz, Al₂SiO₄(F,OH)₂

Chert (Arrowheads)

Microcrystalline Quartz (SiO2)

Jasper

Silicon dioxide (SiO2)

Rounded river cobble, likely basaltic volcanic rock

Fine-grained mafic igneous rock; likely basalt or andesite

Pink quartz (likely rose quartz)

Quartz, silicon dioxide (SiO₂), commonly rose quartz colored by trace impurities and microscopic inclusions

Porphyritic basaltic-andesite

Porphyritic intermediate volcanic rock; chiefly plagioclase and pyroxene/amphibole, with altered mafic minerals and iron oxides

Vesicular quartz-rich rock, possibly weathered rhyolite or silicified volcanic breccia

Silica-rich volcanic rock; likely microcrystalline quartz (SiO₂) with altered feldspar and iron-oxide staining

Banded Sandstone

Arenite (composed primarily of Quartz: SiO2)

Tumbled dark pebble

Indeterminate; likely basalt or fine-grained dark metamorphic rock

Granite or granitic gneiss pebble

Felsic granitoid, chiefly quartz, feldspar, and mica; exact identification is uncertain from the photograph

Sandstone (Ferruginous)

Arenite (with Hematite/Limonite cement)

Chert (specifically Flint or Common Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz-rich rock fragment

Microcrystalline quartz (SiO₂), possibly chalcedony or quartz-bearing breccia

Tumbled beige stone, possibly jasper or limestone

Indeterminate; likely microcrystalline quartz (jasper) or calcium-carbonate limestone

Fossil Coral

Phylum Cnidaria / Rugosa or Tabulata

Chert / Flint

Silicon Dioxide (SiO2)

Dark metamorphic rock, likely biotite schist or gneiss

Quartz–feldspar–biotite metamorphic rock; exact identification requires a fresh surface and testing

Chert (and Jasper/Chalcedony variety)

Microcrystalline Quartz (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Chert (Nodule)

Cryptocrystalline Quartz (SiO2)

Likely weathered iron-rich stone

Uncertain; possibly limonite/goethite-bearing rock

Sandstone (with vugs or solution cavities)

Arenite (primarily Quartz and Feldspar with CaCO3 or SiO2 cement)

Chert (Nodule)

Chert (SiO2)

Chert (Yellow/Brown Jasper)

Silicon Dioxide (SiO2)

Chert (Jasper/Flint Pebble)

Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)

Stromatolite (Jasper-replaced)

Fossilized Stromatolite (Cyanobacteria / Cryptozon / Silica SiO2)

Small rounded pebble, likely quartz-rich stone

Indeterminate from photograph; possibly microcrystalline quartz (SiO₂) or a weathered silicate pebble

Sandstone (Quartz-rich)

Arenite (composed primarily of SiO2)

Chalcedony on Ironstone

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3/FeOOH)

Chert (Jasper/Agate variety)

Silicon Dioxide (SiO2)

Weathered dark rock fragment

Indeterminate; possibly basalt or iron-rich volcanic rock

Chert (Lightly weathered variety)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Likely botryoidal malachite or chrysocolla specimen

Malachite, Cu₂CO₃(OH)₂; possibly chrysocolla, hydrated copper silicate

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

Vesicular Basalt

Basalt (Mafic volcanic rock)

Petrified Wood

Silicified Wood / Xylopal (SiO2)

Likely pale limestone or calcite-rich rock

Calcite-bearing limestone; chiefly calcium carbonate (CaCO₃)

Milky quartz-bearing rock, possibly quartzite

Quartz (SiO₂), likely in a quartzite or quartz-rich metamorphic matrix

Sandstone (Graywacke type)

Clastic Sedimentary Rock (Lithic Sandstone)

Likely porphyritic igneous rock (possibly granite or rhyolite)

Quartz–feldspar–mica aggregate; exact identification requires a fresh surface and tests