Mineral (Biogenic Replacement)

Chalcedony in Matrix (likely Agatized Coral or Chert)

Silicon Dioxide (SiO2)

Orbicular jasper (likely ocean jasper)

Silica-rich microcrystalline quartz/chalcedony with iron-oxide and feldspar inclusions; commonly marketed as Ocean Jasper

Fossil coral fragment

Likely scleractinian coral; calcium carbonate, predominantly aragonite or recrystallized calcite (CaCO₃)

Fossil coral fragment

Likely colonial scleractinian coral; calcite/aragonite (CaCO₃)

Possible fossilized bone or tooth fragment

Indeterminate fossilized vertebrate material; mineralized hydroxyapatite replaced or coated by silica/carbonate

Jasper-Agate (Iron-stained Quartz)

Silicon Dioxide (SiO2) with iron oxide inclusions

Fossil Coral

Scleractinia (Fossilized Coral) / Calcium Carbonate (CaCO3) or Silica (SiO2)

Tiger's Eye

Silicon dioxide (Quartz pseudomorph after crocidolite), SiO2

Red Jasper

Jasper (Silicon Dioxide, SiO2 with iron oxide impurities)

Petoskey Stone

Hexagonaria percarinata (Fossilized Rugose Coral)

Ammonite fossil in matrix

Fossilized ammonoid cephalopod; likely an ammonite such as Dactylioceras or a related Jurassic taxon

Fossilized ammonite

Ammonoidea (likely an ammonite; exact genus indeterminate)

Fossilized Trilobite or Mollusk Fragment

Phylum Arthropoda / Mollusca fossil in sedimentary matrix

Ammonite Fossil

Ammonoidea

Polished petrified wood

Silicified wood; commonly quartz/chalcedony (SiO₂) replacing wood tissue

Flint

SiO2 (Microcrystalline Quartz / Chert)

Yellow Jasper

Quartz (Silicon Dioxide, SiO2 with impurities)

Petrified Wood

Silicified wood (Quartz replacement, SiO2)

Fossil shark tooth in limestone or sandstone matrix

Likely fossilized shark tooth, possibly Carcharodon or Carcharhinus sp.; matrix is probably calcareous sandstone/limestone

Fossil tooth, possibly shark tooth

Indeterminate fossilized vertebrate tooth; likely a shark tooth (possibly *Carcharhinus* or related genus)

Fossilized mammalian tooth fragment

Likely a fossil molar or premolar; exact taxon cannot be determined from the image

Fossil shark tooth, likely megalodon

Fossilized shark tooth; possibly Otodus megalodon (formerly Carcharocles megalodon)

Galena-bearing sulfide specimen

Galena (PbS), likely with sphalerite and/or pyrite gangue

Likely galena-bearing sulfide fragment

Galena (PbS), possibly mixed with sphalerite and/or chalcopyrite

Likely raw metallic sulfide mineral, possibly galena or sphalerite

Uncertain; galena (PbS) or sphalerite (ZnS) are plausible

Purple fluorite cluster

Fluorite (calcium fluoride, CaF₂)

Chalcedony

Silicon Dioxide (SiO2)

Peacock ore (likely chalcopyrite)

Iridescent tarnished chalcopyrite, CuFeS₂; sometimes marketed as bornite, Cu₅FeS₄

Galena-bearing ore (tentative)

Galena, lead sulfide (PbS), likely in a quartz/carbonate-rich matrix

Barite

Barium Sulfate (BaSO4)

Chert (Vuggy or Fossilliferous)

Microcrystalline Quartz (SiO2)

Calcite (likely a tumbled specimen)

Calcite (CaCO 3 )

Lapis Lazuli (Tumbled)

Lazurite-dominated contact metamorphic rock

Petrified Bone (Fossil Bone)

Per mineralization fossil bone (varies by organism, predominantly replacement by SiO2 - Quartz/Chalcedony)

Fossilized Bone (Petrified Bone)

Permineralized Bone Fossil

Petrified Wood

Silicified wood (Quartz / Chalcedony replacement)

Petrified Wood

Silicified Wood (SiO2)

Fossilized Bone

Fossilized Vertebrate Bone (Per mineralized)

Pyrite

Iron Sulfide (FeS2)

Fossilized coral (likely honeycomb or branching coral)

Fossil coral; probable Scleractinia or Tabulata, composition mainly microcrystalline CaCO₃

Fossil shark teeth

Probably fossilized shark teeth, possibly *Otodus* or *Carcharhinus* species

Galena-bearing ore (probable)

Galena, lead sulfide (PbS), possibly with sphalerite or metallic sulfides