Organic Material (Likely A Fruit Or Berry)

Fossiliferous Sedimentary Rock (Coquina/Limestone)

Fossiliferous Calcarenite / Bioclastic Limestone

Petrified Wood

Silicified Wood (primarily Chalcedony/Quartz, SiO2)

Milky quartz with iron-oxide staining

Quartz (silicon dioxide, SiO₂), commonly intergrown massive quartz

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 cement)

Vesicular basalt

Basalt, typically composed of plagioclase feldspar, pyroxene, and minor olivine or iron oxides

Weathered iron-rich sandstone or laterite fragment

Ferruginous sandstone, likely hematite/goethite-cemented sandstone (exact identification requires testing)

Chert / Flint Nodules

Cryptocrystalline Quartz (SiO2)

Tumbled citrine or iron-stained quartz

Quartz (SiO₂), likely iron-oxide-stained or natural citrine

Banded Rhyolite

Rhyolite (High-silica volcanic rock)

Tumbled serpentine (likely)

Serpentine-group minerals, commonly lizardite or antigorite; approximate composition Mg₃Si₂O₅(OH)₄

Granite

Granite (Felsic Plutonic Rock)

Weathered quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂), with possible feldspar, mica, and iron-oxide staining

Weathered quartz-rich rock, likely quartzite or altered sandstone

Quartzite (mostly microcrystalline quartz, SiO₂); exact identification is uncertain from the photograph

Chert (varieties include Flint and Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Galena (likely)

Galena, lead sulfide (PbS)

Chert (Flint)

Microcrystalline Opaline Silica (SiO2)

Man-made Synthetic Material (Plastic/Composite)

Acrylonitrile Butadiene Styrene (ABS) or High-Impact Polystyrene (HIPS)

Shale

Fissile Clay-dominant Mudrock (SiO2, Al2O3, K2O, Na2O, CaO, MgO)

Moss Agate

Silicon Dioxide (SiO2) with inclusions

Tumbled amber

Amber (fossilized plant resin), chiefly polymerized diterpenoid resin

Chert (varieties include Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Gravel)

Silicon Dioxide (SiO2)

Chert (specifically White Chert or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Rounded granitic gneiss or granite cobble

Granite; primarily quartz, plagioclase and potassium feldspar with biotite/hornblende

Chert (often called Flint or Jasper)

Microcrystalline Quartz (SiO2)

Chert (often called Jasper or Flint)

Silicon Dioxide (SiO2)

Glacial Erratic (Sandstone/Quartzite)

Glacial Erratic specimen (likely Orthoquartzite or Feldspathic Sandstone)

Banded Sedimentary Rock (Wishbone Stone / Banded Quartzite or Limestone)

Silicified limestone or banded sedimentary rock with mineral veins

Weathered sandstone cobble

Quartz-rich sandstone, primarily SiO₂ with clay/iron-oxide cement

Rounded basalt cobble (probable)

Basalt; fine-grained mafic volcanic rock, chiefly plagioclase and pyroxene

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily SiO2)

Chert (often called Flint)

Chert (Microcrystalline Silicon Dioxide, SiO2)

Chert

Microcrystalline Quartz (SiO2)

Mixed rock and mineral collection

Mixed lithologies; likely quartz, feldspar, basalt, granite, chert, sandstone, and metamorphic rocks

Small rounded pebble, likely quartz-rich river stone

Indeterminate; likely quartz/chert-bearing lithic clast

Chert (Nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Red Chert (Jasper)

Silicon Dioxide (SiO2)

Chert (specifically Blue or Grey Chert/Flint)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (specifically Flint)

Silicon Dioxide (SiO2)

Chert (Yellow Jasper variant)

Microcrystalline quartz (SiO2)

Green Chert (Jasper)

Microcrystalline Quartz (SiO2) with chlorite/epidote inclusions

Yellow-brown quartz/chalcedony fragment

Quartz, SiO₂; likely microcrystalline chalcedony with iron-oxide staining