Mineral (Biogenic Replacement)

Tiger's Eye (Small Polished Bead)

Pseudomorph of Quartz after Crocidolite (SiO2)

Fossil Coral

Hexagonaria or similar rugose/tabulate coral fossil (Calcium Carbonate, CaCO3)

Magnetite

Magnetite (Fe3O4)

Polished orbicular jasper

Jasper, microcrystalline quartz (SiO₂), with iron oxides and altered volcanic inclusions

metamorphic

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified wood (Quartz replacement)

Weathered fossilized wood (likely petrified wood)

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

Fossilized tooth or bone fragment

Indeterminate fossil; possibly a small fossil tooth or mineralized bone, exact identification requires microscopy

Yellow Jasper

Jasper (Silicon Dioxide with Iron Oxide inclusions), SiO2

Chert Nodule in Limestone

Chert (Microcrystalline Quartz, SiO2) and Limestone (Calcium Carbonate, CaCO3)

Fossil bivalve shell

Fossilized mollusk (Bivalvia), likely an oyster or clam; exact genus requires locality and diagnostic features

Note: Image shows a biological specimen (Rat), not a rock. Representative geological equivalent: Galena (due to lead-grey colors in fur).

Galena (PbS)

Bismuth

Bismuth (Bi)

Chrysocolla-bearing quartz (likely chrysocolla in quartz)

Chrysocolla, hydrated copper aluminosilicate: approximately (Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O, intergrown with quartz (SiO₂)

Banded fluorite

Fluorite (calcium fluoride, CaF₂)

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with inclusions of Iron Oxide)

Likely fossil tooth or tooth fragment

Indeterminate fossilized vertebrate tooth; possibly shark or marine reptile, identification uncertain from the image

Fossil bivalve shell

Calcitic aragonitic bivalve mollusk shell; exact taxon cannot be determined from the image

Trilobite fossil

Fossilized trilobite; exact genus/species indeterminate

Fossil shark tooth

Likely fossilized shark tooth, possibly Otodus or Carcharhinus; exact identification requires a sharper, closer image

Chert (Common Opal/Agate inclusion)

Microcrystalline Quartz (SiO2)

Petrified wood

Silicified fossil wood, commonly quartz/chalcedony (SiO₂)

Petrified wood

Silicified wood; commonly quartz (SiO₂) replacing original woody tissue

Fossil Coral

Rugosa or Tabulata / Hexacorallia (replaced with silica or calcite)

Mammoth Molar Fossil

Mammuthus primigenius (Tooth fragment)

Flint

Sedimentary cryptocrystalline quartz (SiO2)

Metallic sulfide-bearing rock, possibly galena-rich ore

Likely galena (PbS) with iron sulfides and gangue; exact identification requires testing

Fossilized Shark Tooth

Chondrichthyes (Class) fossilized tooth

Polished fossil tooth, likely shark tooth

Fossilized selachian tooth; possibly Otodus or a related lamniform shark

Fossilized Bone Fragment

Permineralized Skeletal Element (Likely Vertebrate)

Dark metallic sulfide specimen, possibly galena

Galena (lead sulfide, PbS), identification tentative

Unidentified metallic mineral or metal-like specimen

Indeterminate from image; possibly galena (PbS) or a metallic sulfide

Galena

Galena (lead sulfide, PbS)

Galena-bearing sulfide ore

Galena (lead sulfide, PbS), possibly with sphalerite and/or pyrite

Magnetite-rich Iron Ore

Magnetite (Fe3O4)

Celestine (or Celestite)

Strontium sulfate (SrSO4)

Celestite (Celestine)

Strontium sulfate (SrSO4)

Ammonite Fossil

Ammonoidea (subclass)

Fossilized coral or bryozoan fragment

Indeterminate colonial coral/bryozoan fossil; likely calcitic calcium carbonate (CaCO₃)

Tumbled red jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), commonly colored by iron oxides