Organic Material (Likely A Fruit Or Berry)

Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Chert / Flint

Microcrystalline or cryptocrystalline quartz (SiO2)

Fossilized cylindrical shell or bone fragment

Indeterminate biogenic carbonate or phosphatic fossil; possible fragment of a tubular shell (e.g., scaphopod) or hollow bone

Tumbled orange chalcedony (likely carnelian)

Microcrystalline quartz, SiO₂; iron-bearing variety commonly termed carnelian

Polished tree agate (likely)

Chalcedony (microcrystalline SiO₂) with green dendritic/inclusion minerals

Chert (specifically Pink/Tan Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Weathered granitic rock fragment

Likely granite or granodiorite, composed mainly of quartz, feldspar, and mica

Chert (Jasper/Chalcedony variety)

Microcrystalline Quartz (SiO2)

Chert (with Quartz veins)

Microcrystalline Quartz (SiO2)

Reddish-brown rounded pebble, likely iron-stained sandstone or chert

Probable quartz-rich sandstone (SiO₂), possibly ferruginous chert; exact identification requires testing

White quartz pebble

Quartz (SiO₂), likely milky quartz

Chert

Microcrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Sandstone (likely Quartz Sandstone)

Arenite (composed primarily of SiO2)

Chert (Flint)

Microcrystalline Silica (SiO2)

Granite boulder

Granite, composed mainly of quartz, alkali feldspar, plagioclase, and minor mica/amphibole

Quartzite Pebble (with iron staining)

Quartzite (SiO2 with ferric oxide impurities)

Chert (specifically Jasper/Flint)

Microcrystalline Quartz (SiO2)

Jasper with Hematite Inclusions

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3)

Weathered quartz-rich rock, likely silicified limestone or quartzite

Microcrystalline quartz (SiO₂), possibly with calcite (CaCO₃) and iron-oxide staining

Quartz-bearing granite or gneiss fragment

Granite/gneiss composed mainly of quartz (SiO₂), feldspar, and minor mica or ferromagnesian minerals

Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Granite

Granite; primarily quartz (SiO₂), feldspar, and mica

Chert (and Limestone) River Cobble

Microcrystalline Quartz (SiO2) within Calcium Carbonate (CaCO3)

Sandstone (Weathered Pebble)

Arenite (primarily SiO2)

Argillite (with Barnacles)

Argillite (metamorphosed mudstone/shale)

Chert (often called Flint or Jasper depending on color)

Chert (SiO2 - Microcrystalline or Cryptocrystalline Quartz)

Weathered sandstone or mudstone

Clastic siliciclastic sedimentary rock, probably quartz-rich sandstone; exact identification requires a fresh surface and tests

Weathered granite-like rock

Coarse-grained granitic rock, likely quartz–feldspar–mica aggregate

Chert (Field Stone/Pebble)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Mixed rock and mineral gravel

Predominantly granite/granodiorite, basaltic rocks, quartz, and possible gneiss; exact identification is uncertain from the image

Milky Quartz with inclusions

Silicon Dioxide (SiO2)

Chert (Chalcedony)

Silicon Dioxide (SiO2)

Chert (Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Pale green calcite

Calcite (CaCO₃), likely crystalline limestone or calcite-rich material

Chert (varietal: Flint or River Pebble)

Silicon Dioxide (SiO₂)

Chert (Iron-stained)

Silicon Dioxide (SiO2)

Chert (Brown Variety)

Microcrystalline quartz (SiO2)

Chert (often called Flint or Jasper)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (with Iron Oxide cement)

Limestone

Calcium carbonate (CaCO3)

Chert with Quartz Veining

Silicon Dioxide (SiO2)