Organic (Biological Specimen)

Amber with inclusion

Amber (Fossilized Tree Resin)

River Stone (likely Mudstone or Siltstone)

Lutite (Clastic sedimentary rock composed of clay and silt-sized particles)

Jasper Agate

Silicon dioxide (SiO2)

Pyrite Geode

Iron Disulfide (FeS2)

Jasper

Jasper (Silicon Dioxide, SiO2)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Chert (Jasper variety)

Microcrystalline Quartz (SiO2)

Chert / Flint

Cryptocrystalline Quartz (SiO2)

Chert Arrowhead (Projectile Point)

Microcrystalline Quartz (SiO2)

Gray Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Chert (often called Flint)

Microcrystalline Quartz (SiO2)

Fossilized Oyster Shell

Gryphaea or Crassostrea fossil (Calcium Carbonate, CaCO3)

Manganese Oxide Crust on Limestone

Manganese Oxides (e.g., Pyrolusite MnO2 or Romanechite) on CaCO3

Potassium-Rich Silicate Clay (inferred from biological context)

Phyllosilicate group (likely Illite or Smectite within surrounding soil substrate)

Jasper

Silicon dioxide (SiO2)

Chert / Flint (with Crinoid Stem Molds)

Microcrystalline Quartz (SiO2)

Chert (River Pebble)

Chert (Microcrystalline Quartz, SiO2)

Fossiliferous Limestone (Coquina / Shell Limestone)

CaCO3 (Calcium Carbonate)

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Agatized Chert)

Microcrystalline Quartz (SiO2)

Sandstone Pebble

Arenite (primarily SiO2)

Petrified Wood

Silicified wood (Quartz/Chalcedony/Opal replacing organic matter)

Piddock-bored Mudstone

Lutite (Siltstone or Mudstone) with Pholad borings

Chert (with Limestone matrix)

Silicon dioxide (SiO2)

Tufa

Calcareous Tufa (CaCO3)

Fossil Bivalve Shell

Class Bivalvia (e.g., Veneriidae family)

Fossiliferous Limestone with Brachiopod

Phylum Brachiopoda in calcitic matrix

Chert (Arrowhead Preform)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (Jasper-bearing)

Microcrystalline silica (SiO2) with iron oxide inclusions

Chert (Jasper/Common Opal mix)

Microcrystalline Quartz (SiO2)

Chert (often called Flint when dark or worked)

Cryptocrystalline silica (SiO2)

Chert (Yellow Jasper variant)

Microcrystalline Quartz (SiO2)

Chert (Arrowhead/Tool variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Limestone with Chert or Siltstone bands

Sedimentary carbonate rock (CaCO3) often with siliceous impurities

Chert (Jasper/Flint variety)

Microcrystalline quartz (SiO2)

Chert (Basanite / Flint)

Microcrystalline silica (SiO2)

Chert (variations include Flint or Jasper)

Silicon Dioxide (SiO2)

Chert (Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone (likely Fossiliferous Sandstone)

Clastic sedimentary rock (primarily SiO2)

Chert (Fossiliferous)

Silicon dioxide (SiO2)

Chert (Beach Pebble)

Microcrystalline Quartz (SiO2)