Organic Specimen (Fossil)

Petrified Wood

Silicified Wood (SiO2)

Fossiliferous Limestone (containing Brachiopods)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Chert (Tan/Grey variety)

Silicon Dioxide (SiO2)

Chert (specifically Tan Chert or Flint)

Silicon Dioxide (SiO2)

Moss Agate

Chalcedony (Silicon Dioxide, SiO2) with dendritic inclusions

Green Chert (Jasper)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Septarian Nodule (Dragon Stone)

Septarian concretion (composition: CaCO3 - Calcite, Aragonite, and Siderite/Limestone)

Petrified Dinosaur Bone (Gembone)

Agatized Dinosaur Bone

Chert (Green Jasperiod)

Chert (Microcrystalline Quartz, SiO2)

Ammonite Fossil

Ammonoidea (typically preserved as Calcite CaCO3 or Pyrite FeS2)

Chert (often called Flint when in chalk or limestone)

Silicon Dioxide (SiO₂)

Gastropod Steinkern (Fossilized Snail Cast)

Phylum Mollusca, Class Gastropoda (Commonly CaCO3 or SiO2 after replacement)

Shale

Shale (clastic sedimentary rock)

Pearl (Biogenic Mineraloid)

Calcium carbonate (Aragonite) and Conchiolin, CaCO3

Sandstone (Micaceous/Feldspathic variant)

Arenite (specifically subarkose or lithic arenite)

Sandstone

Arenite (composed primarily of SiO2)

Chert (often called Flint)

Chert (Microcrystalline Quartz, SiO2)

Piddock bored rock (Boring Stone)

Ichnofossil-bearing Limestone or Mudstone (trace fossils by Pholadidae)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Sandstone

Arenite (primarily SiO2)

Moss Agate

Silicon Dioxide (SiO2) with Manganese or Iron Oxide inclusions

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Chalcedony variety)

Microcrystalline Quartz (SiO2)

Ammonite Fossil

Ammonoidea (subclass)

Moss Agate

Silicon Dioxide with inclusions (SiO2 + impurities)

Septarian Nodule

Septarian Concretion

Chert (specifically Flint or Novaculite variant)

Chert (Microcrystalline Quartz, SiO2)

Sandstone (with potential trace fossils)

Clastic sedimentary rock (primarily SiO2)

Chert (Nodule)

Microcrystalline Quartz (SiO2)

Pyrite

Iron Sulfide (FeS2)

Chert (Jasper variation)

Microcrystalline Quartz (SiO2)

Fossil Shell in Sedimentary Matrix

Bivalvia (fossil) in Calcium Carbonate Matrix

Chert (Commonly known as Flint or Jasper when pigmented)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Massive Cryptocrystalline Quartz (Chert/Chalcedony Pebble)

Silicon Dioxide (SiO2)

Chert (specifically Iron-stained River Cobble)

Silicon Dioxide (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Jasper (Mookaite variety likely)

Silicon Dioxide (SiO2) with iron oxide inclusions

Jasper

Agate/Jasper (Microcrystalline Quartz, SiO2)

Chert (Yellow Jasper variant)

Microcrystalline Quartz (SiO2)

Chert (Brecciated or Veined)

Silicon Dioxide (SiO2)

Limestone (Flagstone)

Fossiliferous Limestone (CaCO3)

Chert with Quartz/Calcite Vein

Microcrystalline Silica (SiO2)