Organic Material (Likely A Fruit Or Berry)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Man-made Carved Stone (Scream Mask/Skull motif)

Carved Soapstone or Serpentine-rich rock

Possible iron-rich concretion or weathered ironstone

Goethite/limonite-rich ironstone; exact identification requires testing

Chert (specifically Flint or Gray Chert)

Silicon Dioxide (SiO2)

Chert (variations include Flint/Novaculite)

Chert (formula: SiO2)

Chert (Arrowhead Artifact)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Blue Lace Agate (with Amethyst Geode center)

Silicon Dioxide (SiO2) - Cryptocrystalline Chalcedony

Quartzite Geode (unopened)

SiO2 (Silicon Dioxide)

Jasper

Silicon dioxide (SiO2) with impurities

Jasper

Silicon Dioxide (SiO2) with impurities

Green Jasper

Silicon Dioxide (SiO2) with impurities of iron(II) silicate

Yellow Jasper / Chert

Jasper (Silica/Quartz) - SiO2

Chert (Yellow/Brown variety)

Chert (SiO2)

Weathered quartz-rich pebble, possibly milky quartz or chalcedony

Quartz, SiO₂; exact variety uncertain from the image

Chert (and Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

River Stone (likely Quartzite or Limestone)

Silicon dioxide (SiO2) or Calcium carbonate (CaCO3)

Petrified Wood

Silicified wood (primarily Silicon Dioxide, SiO2)

Petrified Wood

Silicified Wood (SiO2)

Weathered fine-grained stone, likely sandstone or quartzite

Quartz-rich sandstone (possibly weakly metamorphosed quartzite); predominantly SiO₂

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (Yellow or Brown Jasper)

Microcrystalline Quartz (SiO2)

Chert (often called Flint or River Stone)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (SiO2)

River-worn Chert

Microcrystalline Quartz (SiO2)

Chert (often called Jasper in this color variety)

Microcrystalline Quartz (SiO2)

Fossilized Tiger Shark Tooth

Galeocerdo cuvier (fossilized hydroxylapatite)

Rounded greenstone pebble

Likely serpentinite or chlorite-rich metamorphic rock; exact identification requires testing

Weathered sandstone or quartz-rich sedimentary pebble

Indeterminate lithic fragment; likely quartz arenite (sandstone)

Chert (specifically Gray/Black Chert)

Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)

Weathered quartz-rich pebble (probable quartzite or quartz vein fragment)

Quartzite, predominantly silicon dioxide (SiO₂); exact identification is uncertain from the photograph

Sandstone (Ferruginous)

Arenite (Fe2O3 enriched)

Rough Chalcedony / Jasper Agate Nodule

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Fancy Jasper (Agate/Chert mix)

Silicon Dioxide (SiO2) with impurities

Red Jasper

Jasper (Silicon Dioxide, SiO2 with iron oxide impurities)

Chert (Jasper/Chalcedony Pebble)

Silicon Dioxide (SiO2)

Sandstone (Quartz-rich)

Clastic sedimentary rock (SiO2 primary)

Gravelly, weathered sediment (likely glacial till)

Unconsolidated diamicton; mixed lithologies, commonly including quartz, feldspar, and weathered silicate rock fragments

Jasper / Chert (River Pebble)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Lepidodendron Fossil (Scale Tree)

Lepidodendron

Petrified Wood

Silicon Dioxide Fossilized Wood (SiO2)

Jasper (Brown Iron-Rich Variety)

Silicon Dioxide (SiO2) with Fe2O3 (Iron Oxide/Crystalline Quartz)