Weathered quartz-rich cobble, possibly quartzite or feldspar-rich granite
Quartz–feldspar aggregate; identification is uncertain from the photograph
igneous
Category
Mineral, Sediment
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Sandstone
Arenite (primarily SiO2)
sedimentary
Fossil bivalve shell
Fossilized or partially mineralized bivalve; exact genus cannot be determined from the image
fossil
Desert Rose
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
mineral
Pitted Limestone
Calcium Carbonate (CaCO3)
sedimentary
Sandstone (with potential trace fossils)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Sand
Siliciclastic sediment / Quartz sand (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Petrified Wood and Mixed Rocks
Silicified Wood (SiO2)
fossil
Shale
Shale (Sedimentary rock composed of mud/clay minerals)
sedimentary
Jasper (likely Polychrome or Mookaite variants)
Silicon Dioxide (SiO2) with iron oxide and hydroxide inclusions
sedimentary (chemically precipitated)
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Gold Flake
Native Gold (Au)
mineral
Ferruginous Sandstone
Clastic Sedimentary Rock (Iron-rich)
sedimentary
Quartz (milky quartz), possibly calcite
Quartz: SiO₂; visual identification is uncertain because the specimen is wet and lacks diagnostic crystal faces
mineral
Fossil shell fragment (likely brachiopod or bivalve)
Indeterminate fossilized carbonate shell; likely Brachiopoda or Bivalvia
fossil
Yellow Jasper
Tectosilicates (SiO2) with Goethite/Iron oxide inclusions
sedimentary
Drupa Quartz (Sparkly Drusy Quartz on Matrix)
Crystalline Silicon Dioxide (SiO2) on host rock
mineral
Shale (possibly Carbonaceous or Oil Shale)
Laminated Mudstone (primarily clay minerals and quartz)
sedimentary
Marble
Metamorphic Limestone (Calcite, CaCO3)
metamorphic
Ironstone Nodules (Iron Concretion)
Siderite or Hematite Concretion
sedimentary
Fossil / Permineralized Bone
Tyrannosaurus rex fossil (Hydroxylapatite replaced by various minerals)
sedimentary
Yellow Jasper
Chalcedony (SiO2 with iron oxide inclusions)
mineral
Limonite (Ironstone Concretion)
Limonite (FeO(OH)·nH2O)
mineral/sedimentary
Coarse Sand and River Gravel
Siliciclastic Sediment (primarily Quartz and Feldspar)
sedimentary
Fossilized Shark Tooth
Chondrichthyes tooth
fossil
Fossilized Shark Tooth
Chondrichthyes (class) fossilized tooth
fossil
Fossilized bivalve shell fragment
Fossil Mollusca, likely a bivalve (class Bivalvia); exact genus cannot be determined from the image
fossil
Iron-rich brown stone, possibly weathered chert or ironstone
Undetermined; likely iron-oxide-bearing silica-rich rock (chert/ironstone)
sedimentary
Fossilized Gastropod Internal Mold
Steinkern (Mollusca: Gastropoda)
sedimentary
Marble
Recrystallized Carbonate Rock (CaCO3)
metamorphic
Banded Chert / Sandstone Pebble
Microcrystalline Quartz (SiO2) / Silicified Sandstone
sedimentary
Tumbled, weathered limestone or calcareous concretion
Calcite-rich limestone; predominantly calcium carbonate (CaCO₃)
sedimentary
Banded Sedimentary Rock
Stratified Siliciclastic / Arenite or Siltstone with Mineral Bands
sedimentary
Petrified Coral Fossil (Honeycomb Coral)
Favosites (Rugosa/Tabulate coral fossil replaced by microcrystalline quartz/chalcedony)
fossil
Banded Sandstone (River Cobble)
Arenite Sandstone with heavy mineral layering
sedimentary
Quartz-Veined Mudstone
Argillaceous Mudstone with Quartz Veining
sedimentary
Tumbled reddish sandstone pebble
Quartz-rich sandstone, likely ferruginous arkose or quartz arenite
sedimentary
Sandstone (River Pebble)
Arenite
sedimentary