Organic Specimen (Fossil)

Chert (Nodule)

Silicon Dioxide (SiO2)

Chert (with Quartz Druzy)

Microcrystalline Silica (SiO2)

Chert (Jasper influence)

Microcrystalline Quartz (SiO2)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Amber-bearing Coal/Sedimentary Rock

Bituminous coal or carbonaceous siltstone with Fossilized Tree Resin (C10H16O)

Fossil / Permineralized Bone

Tyrannosaurus rex fossil (Hydroxylapatite replaced by various minerals)

Weathered iron-rich sandstone or ironstone cobble

Ferruginous sandstone/ironstone, chiefly quartz (SiO₂) cemented or stained by iron oxides and hydroxides

Graphite

Graphite (Carbon, C)

Sandstone (likely Graywacke or Arkose variant)

Clastic Sedimentary Rock (Lithic Sandstone)

Chert (Iron-stained)

Silicon Dioxide (SiO2)

Jasper with Agate and Quartz Inclusions

Silicon Dioxide (SiO2) - Chalcedony / Quartz aggregate

Shale

Fissile Clay-dominant Mudrock (SiO2, Al2O3, K2O, Na2O, CaO, MgO)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Sandstone

Arenite (primarily SiO2 with iron oxide cementation)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Flint (chert), possibly fossil-bearing

Microcrystalline quartz (SiO₂), chalcedony/flint variety

Fossilized bivalve or brachiopod shell

Indeterminate calcitic shell fossil; likely Bivalvia or Brachiopoda

Fossilized Chiton (Polyplacophora)

Polyplacophora (fossilized valves)

Limonite-stained Chert

Microcrystalline Quartz (SiO2) with Hydrated Iron Oxides (FeO(OH)·nH2O)

Shale

Shale (fine-grained clastic sedimentary rock)

Fossiliferous Limestone (Coral Fossil)

Calcium Carbonate (CaCO3) with Colonial Coral inclusions

Pyrite

Iron Sulfide (FeS2)

Chert (specifically a stream-worn Chert Nodule)

Sedimentary Cryptocrystalline Quartz (SiO2)

Shale with Plant Fossils / Carbonaceous Shale

Laminated Mudrock (Siliciclastic)

Sandstone

Arenite (SiO2 principal component)

Weathered sandstone or iron-stained sedimentary rock

Likely quartz-rich sandstone; exact identification is uncertain from the photograph

Petrified Wood

Silicified Wood (SiO2)

Chert (River Pebble)

Silicon Dioxide (SiO2)

Calamites Fossil (Horsetail Stem)

Calamites (Genus), part of the class Equisetopsida

Chert (Arrowhead Artifact)

Microcrystalline Quartz (SiO2)

Chert Arrowhead

Cryptocrystalline Quartz (SiO2)

Chert

Microcrystalline Quartz (SiO2)

Chert / Jasper

Silicon Dioxide (SiO2)

Chert (Jasper/Flint variety)

Silicon dioxide (SiO2) - Microcrystalline Quartz

Chert (and Jasper/Flint variety)

Cryptocrystalline Quartz (SiO2)

Chert (within Asphalt)

Chert (SiO2)

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Asphalt (Bituminous pavement)

Bituminous concrete / Asphalt

Sandstone (Quartz-rich Pebble)

Arenite (primarily SiO2)

Bituminous Coal

Organic Sedimentary Rock (composed mostly of carbon with sulfur and hydrogen)

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert

Microcrystalline Quartz (SiO2)