Anthropogenic (Man Made Material Mimicking Sedimentary Rock)

Tufa

Calcareous Tufa (CaCO3)

Painted Garden Rock (likely Granite or Limestone base)

Silicon Dioxide (SiO2) / Calcium Carbonate (CaCO3) based substrate with Acrylic/Enamel pigments

Chert (Quartz Variety)

Silicon Dioxide (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Gneiss

Gneiss (High-grade metamorphic rock)

Quartz-bearing metamorphic rock, likely garnet-mica schist

Quartz–mica schist with probable garnet and iron-oxide minerals

Conglomerate with Fossilized Shark Teeth

Clastic sedimentary rock (Conglomerate) containing Elasmobranchii remains

Jasper Agate (specifically Brecciated Jasper with Agate inclusions)

Silicon Dioxide (SiO2)

Chrysocolla on Matrix

Hydrated copper silicates ((Cu,Al)2H2Si2O5(OH)4·nH2O)

Agate (specifically, multi-colored or pastel-dyed agate)

Silicon dioxide (SiO2) - specifically, a cryptocrystalline variety of quartz known as Chalcedony, with banding classified as Agate. (If it were Fluorite, the chemical formula would be Calcium Fluoride - CaF2).

Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Weathered quartz-rich rock, likely milky quartz or quartzite

Quartz (SiO₂), possibly quartzite with iron-oxide staining

Chert / Pink Chert

Silicon Dioxide (SiO2)

Banded gneiss pebble

Gneiss, likely quartz–feldspar–mica gneiss

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Polished brecciated jasper (likely septarian or iron-rich jasper)

Microcrystalline quartz (chalcedony), SiO₂, with iron oxides and possibly calcite or other rock fragments

Likely weathered quartz-bearing rock (uncertain identification)

Possibly quartz-rich granite or granitic aplite; exact identification requires a clearer, larger image and tests

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified Wood (primarily Quartz / Chalcedony: SiO2)

Chert (Field Stone)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Biotite (Mica)

Biotite group (K(Mg,Fe)3AlSi3O10(F,OH)2)

Anthracite Coal

Anthracite (Carbon C)

Vein-bearing sandstone or quartzite cobble

Quartz-rich sandstone with white quartz veins; possibly metamorphosed to quartzite

Likely weathered river pebble

Indeterminate lithology; possibly fine-grained sandstone, siltstone, or chert

Quartz

Quartz (SiO₂ - Silicon Dioxide)

Sandstone with trace fossil

Sandstone, possibly with Skolithos or similar trace fossil

Sandstone (with possibly iron oxides and other minerals)

Sandstone

Greywacke (River Pebble)

Greywacke sandstone with quartz veining

Sandstone

Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)

Chert (variously identified as Flint)

Microcrystalline Quartz (SiO2)

Weathered sandstone or iron-rich mudstone fragment

Clastic sedimentary rock, likely quartz–feldspar sandstone with iron-oxide cement

Banded limestone or marble

Calcite-dominated carbonate rock; likely banded marble (CaCO₃)

Ferruginous Sandstone

Sandstone, Iron-rich

Metallic sulfide ore, likely pyrite-bearing rock

Pyrite (FeS₂), possibly with marcasite or other sulfides

Jasper (Imperial Jasper style)

Silicon Dioxide (SiO2) with impurities

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Quartz (Rock Crystal) with minor impurities

Quartz (SiO2)

Chert (specifically Iron-stained River Cobble)

Silicon Dioxide (SiO2)

Opalite

Synthetic opalescent glass

Chert (and Jasper blend)

Chert (Microcrystalline Quartz, SiO2)