Organic Gemstone (Fossilized Resin)

Chert (Chalky/Gray Variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Brown Variety)

Silicon dioxide (SiO2)

Brachiopod Fossil (Spiriferid)

Phylum Brachiopoda, Order Spiriferida (CaCO3 - Calcium Carbonate)

Brachiopod Fossil (Spiriferid)

Order Spiriferida (Phylum Brachiopoda); mineralized as Calcite (CaCO3) or Chert (SiO2)

Fossilized Coral (Petoskey Stone / Favosites)

Favosites (extinct genus of tabulate coral)

Gastropod Steinkern (Fossilized Snail Cast)

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

Chert (varietal Flint or Jasper)

Microcrystalline Quartz (SiO2)

Chert (specifically Red Chert/Jasper variety)

Silicon Dioxide (SiO2)

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint Nodules)

Chert (Microcrystalline Quartz, SiO2)

Slate

Slate (a fine-grained, foliated metamorphic rock). Mineral composition: Primarily composed of mica minerals (muscovite, chlorite, sericite) and quartz, with minor amounts of hematite, pyrite, and other accessory minerals.

Mother of Pearl (Nacre)

Aragonite (CaCO3) with Organic Matrix

Chert (White-Tan variety)

Silicon dioxide (SiO2) / Microcrystalline Quartz

Fossiliferous Chert (Gryphaea Fossil)

Silicon Dioxide (SiO2) with Calcitic Mollusk Remnants

Fossilized Favosites (Honeycomb Coral)

Favosites (extinct genus of tabulate coral)

Fossilized Gastropod in Chert/Limestone

Internal mold of Gastropoda (Class) with CaCO3 or SiO2 mineral formula

Fossilized Stingray Mouth Plate

Myliobatidae dental battery

Fossilized Solitary Rugose Coral

Order Rugosa (commonly Horn Coral)

Fossilized Coral (Honeycomb Coral)

Favosites (extinct genus of tabulate corals), CaCO3 (Calcium Carbonate)

Fossilized Shark Tooth in Matrix

Otodus sp. (likely Otodus obliquus)

Fossilized Sea Urchin (Echinoid)

Echinoidea (Class); commonly Clypeasteroida for sand dollar types

Crinaudite / Fossilized Crinoid Stem

Crinoid (Echinodermata) in a Calcitic/Siliceous Matrix

Chert (specifically Tan/Yellow Chert)

Chert (Microcrystalline or Cryptocrystalline Silica, SiO2)

Sandstone with trace fossil

Sandstone, possibly with Skolithos or similar trace fossil

Chert (Nodular)

Chert (SiO2 - Microcrystalline Quartz)

Chert (Commonly known as Flint or Jasper when pigmented)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (variations include Flint/Jasper)

Cryptocrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline or cryptocrystalline quartz (SiO2)

Yellow Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Chert (Iron-rich variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper variety)

Chert (SiO2)

Chert (often called Flint when dark)

Chert (Microcrystalline or Cryptocrystalline Silica, SiO2)

Fossilized Shark Tooth (Cretaceous to Neogene)

Elasmobranchii dental fossil (likely Squalicorax or similar species)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Chert (Commonly known as Flint)

Microcrystalline Quartz (SiO2)

Chert (Flint variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Red Jasper

Jasper (Silicon Dioxide, SiO2 with iron oxide impurities)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert / Flint

Cryptocrystalline Quartz (Silicon Dioxide, SiO2)

Chert (often called Flint or Jasper)

Chert (Microcrystalline or Cryptocrystalline Silica, SiO2)

Chert (varieties include Flint and Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Horse Chestnut (Buckeye seed)

Aesculus hippocastanum seed