Mineral, Sediment

Sandstone Concretion

Ferruginous Sandstone Concretion

Sandstone (likely Greywacke variant)

Arenite

Sandstone Concretion

Sedimentary Clastic Rock (Silicate-rich)

Petrified Wood

Silicified Wood (primarily SiO2)

Ironstone Nodules (Iron Concretion)

Siderite or Hematite Concretion

Fossil / Permineralized Bone

Tyrannosaurus rex fossil (Hydroxylapatite replaced by various minerals)

Weathered granite or granitic gneiss

Granite; chiefly quartz, feldspar, and biotite/hornblende

Fossiliferous limestone pebble

Calcite-rich limestone (primarily CaCO₃), with possible fossil or fossil-fragment patterns

River Pebble (Gravel Pebble)

Stream-rounded Rock / Siliciclastic Pebble

Petrified Wood

Silicified Wood (SiO2)

Gold Flake

Native Gold (Au)

Ferruginous Sandstone

Clastic Sedimentary Rock (Iron-rich)

Fossil bivalve shell

Fossilized or partially mineralized bivalve; exact genus cannot be determined from the image

Likely dark rounded stone or mineral fragment

Indeterminate; possibly a water-worn mafic rock such as basalt

Sandstone

Arenite (primarily SiO2)

Spinosaurus fossil (permineralized bone)

Spinosaurus aegyptiacus (Calcium phosphate mineralized with silica/sediment)

Fossilized shell or bone fragment

Likely bioclast composed mainly of calcium carbonate (calcite/aragonite); exact organism is indeterminate from the image

Shale

Laminated Mudstone

Likely quartz pebble

Quartz (silicon dioxide, SiO₂), possibly milky quartz

Fossilized oyster shell in limestone

Bivalvia fossil; chiefly calcite (CaCO₃)

Weathered polymictic gravel/conglomeratic rock

Polymictic conglomerate or poorly lithified alluvial gravel; chiefly quartz, feldspar, mica, and dark lithic fragments

Petrified Wood and Mixed Rocks

Silicified Wood (SiO2)

Polished ammonite fossil

Ammonite, an extinct cephalopod; commonly polished specimens are from Jurassic or Cretaceous forms

Fossil oyster shell

Fossilized bivalve, likely an oyster (family Ostreidae); exact genus and age are indeterminable from the image

Fossil bivalve shell

Bivalvia; shell composed mainly of calcium carbonate (typically aragonite and/or calcite)

Fossilized bivalve shell fragment

Fossil Mollusca, likely a pectinid or related bivalve; exact identification requires the other shell half and locality

Quartz (milky quartz), possibly calcite

Quartz: SiO₂; visual identification is uncertain because the specimen is wet and lacks diagnostic crystal faces

Fossil shell fragment (likely brachiopod or bivalve)

Indeterminate fossilized carbonate shell; likely Brachiopoda or Bivalvia

Yellow Jasper

Tectosilicates (SiO2) with Goethite/Iron oxide inclusions

Likely iron-stained quartz or feldspar fragment

Quartz (SiO₂) or potassium feldspar (KAlSi₃O₈), uncertain from image

Shark Tooth Fossil

Carcharodon / Otodus fossilized tooth (Calcium Phosphate / Hydroxyapatite)

Fossilized Shark Tooth

Chondrichthyes (Class)

Calamites (Fossil)

Calamites sp. (Tracheophyta, Equisetopsida)

River Pebble (Gravel)

Rounded clastic sediment

Fossilized gastropod (snail)

Gastropoda; shell commonly preserved as calcite (CaCO₃)

Weathered quartz-rich cobble, possibly quartzite or feldspar-rich granite

Quartz–feldspar aggregate; identification is uncertain from the photograph

Sandstone (with potential trace fossils)

Clastic sedimentary rock (primarily SiO2)

River Rock

Polished Siliceous Rock / Quartzite Pebble

Mixed River Pebbles and Jasper

Siliciclastic sediment and microcrystalline quartz

Fossilized Shark Tooth

Chondrichthyes (class) fossilized tooth

Banded jasper / iron-rich chert (probable)

Microcrystalline quartz (SiO₂) with iron oxides/hydroxides and clay minerals

Conglomerate (or Breccia)

Clastic Sedimentary Rock (Conglomeratic)