Mineral (Biogenic Replacement)

Orbicular jasper (likely ocean jasper)

Silicified microcrystalline quartz/chalcedony, commonly called Ocean Jasper; predominantly SiO₂ with iron-oxide inclusions

Horn Coral Fossil

Rugosa (Order Rugosa)

Fossilized cylindrical shell or bone fragment

Indeterminate biogenic carbonate or phosphatic fossil; possible fragment of a tubular shell (e.g., scaphopod) or hollow bone

Enrolled Trilobite Fossil

Phylum Arthropoda, Class Trilobita (likely Calymene or Flexicalymene)

Fossilized bivalve shell

Calcitic or aragonitic mollusk shell, commonly Bivalvia; exact species indeterminate

Black Jasper

Silicon Dioxide (SiO2) with impurities

Galena (likely argentiferous galena)

Galena, PbS; commonly cubic or massive lead sulfide, sometimes containing silver

Galena-bearing sulfide fragment

Galena (PbS), possibly with quartz or carbonate gangue

Quartz-bearing sulfide ore, possibly pyrite in altered host rock

Likely pyrite (FeS₂) with quartz and possibly calcite or carbonate gangue; exact identification requires testing

Rhodonite

Rhodonite (Manganese Silicate), (Mn,Fe,Mg,Ca)SiO3

Epidote–garnet skarn (probable copper-bearing alteration rock)

Calc-silicate skarn; likely epidote, garnet, chlorite, quartz/calcite, and iron oxides/sulfides

Dinosaur Bone (Petrified/Agatized)

Permineralized Dinosauria Bone (Silicate Replacement)

Black Chert (Flint)

Silicon Dioxide (SiO2)

Weathered iron-rich rock, possibly limonite-bearing sandstone or altered volcanic rock

Limonite/goethite mixture; exact host rock is indeterminate from the image

Spinosaurus aegyptiacus Fossil

Spinosaurus aegyptiacus (permineralized hydroxyapatite)

Petrified Wood

Silicified Wood (SiO2)

Fossilized oyster shell

Bivalvia; likely an oyster (Ostreidae), partly mineralized with calcite

Pyrite (fool’s gold)

Iron disulfide, FeS₂; commonly cubic or pyritohedral crystals

Polished brown agate or chert pebble

Microcrystalline quartz (SiO₂), likely chalcedony/agate or jasper-rich chert

Dyed, polished stone—possibly rhodonite or pink jasper

Likely rhodonite (MnSiO₃) or manganese-rich jasper; exact identification requires testing

Quartz-rich rock, likely chert or chalcedony

Microcrystalline silica (SiO₂), possibly quartz/chalcedony

Tiger's Eye (and Hematite/Jasper Matrix)

SiO2 (Pseudomorph of Quartz after Crocidolite) with Hematite/Magnetite

Lepidodendron fossil (Scale Tree Bark)

Lepidodendron (Lycophytina class)

Jasper (Red-Brown)

Silicon Dioxide (SiO2) with Iron Oxide impurities

Jasper

Jasper (Silicate mineral, SiO2)

Galena

Lead Sulfide (PbS)

Fossil Coral

Rugose Coral or Tabulate Coral (Phylum Cnidaria)

Petrified Wood

Silicified wood (Quartz/Chalcedony replacement)

Muscovite Schist

KAl2(AlSi3O10)(OH)2 (Muscovite) in Schist Matrix

Jasper with Quartz Vein

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)

Red Jasper Concretion

Cryptocrystalline Quartz (SiO2)

Chert (varieties include Flint and Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint variety)

Silicon dioxide (SiO2) - Microcrystalline Quartz

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Banded aragonite (often sold as banded calcite or “onyx marble”)

Aragonite, CaCO₃; commonly an aragonite–calcite carbonate aggregate

Pyrite on quartz matrix

Pyrite (FeS₂), likely with quartz (SiO₂) and possibly calcite or clay matrix

Peacock ore

Iridescent chalcopyrite, commonly marketed as bornite

Purple fluorite (likely cubic crystal aggregate)

Fluorite, calcium fluoride (CaF₂)

Horn Coral Fossil

Rugose coral (Order Rugosa)

Chert (Jasper)

Silicon dioxide (SiO2)