Mineral, Sediment

Sand and Gravel (Quartz-rich)

Unconsolidated fluvial/beach sediment (primarily Silica/SiO2)

Polished fossil coral

Fossilized colonial coral, commonly Hexagonaria (Petoskey stone) or related rugose/tabulate coral

Yellow jasper (likely iron-rich chert)

Microcrystalline quartz, SiO₂, colored by iron oxides/hydroxides

Petrified Wood

Silicified Wood (SiO2)

Weathered greenish-gray rock fragment, likely chlorite-rich schist

Tentatively chlorite schist; exact identification requires closer examination

Banded iron formation fragment (likely hematite–magnetite ironstone)

BIF; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and silica as microcrystalline quartz (SiO₂)

Weathered iron-rich rock, possibly limonite-bearing sandstone or laterite

Goethite–hematite (FeO(OH)–Fe₂O₃) in a silicate-rich matrix; exact identification requires testing

Shark Tooth Fossil

Elasmobranchii fossil (likely Carcharias or Odontaspis sp.)

Red jasper (probable)

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

Petrified Wood Fragment

Silicified Wood (SiO2)

Sandstone Chert Concretion

Silica-cemented Concretion (primarily SiO2)

Petrified Wood

Silicified wood (Quartz/Chalcedony - SiO2)

Sandstone Concretion

Clastic Sedimentary Concretion (SiO2 with Iron Oxide)

Ironstone Concretion (Pot Stone)

Siderite or Limonite Concretion (FeCO3 or FeO(OH)·nH2O)

Sandstone Concretion

Moqui Marble / Iron-oxide Concretion (SiO2 with Hematite/Goethite)

Picture Jasper (specifically Biggs or Deschutes variety)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Jasper

Silicon dioxide (SiO2)

Fossilized tooth, likely shark tooth

Fossil selachian tooth; possibly Otodus/Carcharocles or related shark, identification uncertain from image

Fossil shell fragment

Indeterminate mollusk shell; likely gastropod or bivalve, composed mainly of calcium carbonate (aragonite/calcite)

Megalodon Tooth

Otodus megalodon

Fossilized shark teeth in sedimentary matrix

Elasmobranchii teeth, chiefly shark; calcium-phosphate apatite (hydroxyapatite)

Polished fossil ammonite pendant

Ammonite fossil, commonly a heteromorph or planispiral ammonoid; chamber walls are calcite-replaced aragonite

Weathered sandstone or siltstone pebble

Clastic sedimentary rock, likely quartz-rich sandstone (dominantly SiO₂)

Petrified Wood

Silicified Wood (SiO2)

Polished brown jasper pebble

Jasper, a microcrystalline variety of quartz (SiO₂), typically with iron-oxide inclusions

Quartz geode

Quartz (SiO₂), likely a quartz-lined geode in a carbonate-rich host

Petrified Wood

Silicified Wood (primarily Silicon Dioxide, SiO2)

Red jasper (likely tumbled jasper/chert)

Microcrystalline quartz, SiO₂, colored red by iron oxides; exact identification from the photo is uncertain.

Jasper containing fossilized inclusions

Silicon Dioxide (SiO2) with trace impurities and biogenic inclusions

Pyrite in Matrix (Fool's Gold)

Iron Sulfide (FeS2)

Fossilized shell fragment

Bioclastic carbonate, likely a bivalve or brachiopod shell preserved as calcite/aragonite

Fossil bivalve shell, likely oyster or related mollusk

Fossilized oyster-like bivalve; exact genus and age cannot be determined from the photograph

Fossil Shark Tooth

Elasmobranchii (Lamniformes order likely)

Orange Quartz (likely Carnelian or stained Quartz)

Silicon Dioxide (SiO2)

Rounded greenish stone, likely basalt or metamorphic greenstone

Probable fine-grained mafic rock; possible basalt (plagioclase–pyroxene) or greenschist-facies greenstone

Vesicular volcanic pebble, likely pumice or vesicular andesite

Pumice (volcanic glass) or vesicular andesite; exact identification requires examination

Red Jasper

Silicon dioxide (SiO2) with iron oxide (Hematite) inclusions

Concretion

Calcareous/Siliceous Concretion

Sandstone (with Laminations)

Clastic sedimentary rock (primarily Quartz-based)

Fossil bivalve shell

Fossilized or calcitic bivalve, likely a scallop-type pectinid (Bivalvia: Pectinidae)

Fossil bivalve or brachiopod in sedimentary rock

Unidentified fossil shell impression; likely a ribbed bivalve or brachiopod preserved in shale/siltstone

Polished fossilized ammonite or nautiloid shell

Ammonoidea or Nautiloidea; originally aragonitic shell, commonly replaced by calcite or chalcedony