Rock

Rounded gray river pebble, likely basalt or andesite

Fine-grained mafic to intermediate volcanic rock; commonly basalt (plagioclase ± pyroxene/olivine)

River Cobble (Weathered Granitoid)

Granodiorite / Quartz Diorite

Shale with Quartz Veins

Fissile Sedimentary Rock (SiO2)

Granite

Intrusive Igneous Rock

Basalt Pebble

Extrusive Igneous Rock (Mafic)

Basalt

Extrusive mafic igneous rock

Breciated Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Sandstone

Arenite (primarily SiO2)

Brachiopod Fossil

Phylum Brachiopoda

Vesicular Basalt with Quartz/Chalcedony

Vesicular Basalt (primarily Plagioclase, Pyroxene, and Olivine with SiO2 infill)

Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Basalt

Basalt

Gneiss

Gneiss

Gabbro (or Basalt Pebble)

Mafic Intrusive/Extrusive Igneous Rock

Chert / Flint

Microcrystalline quartz (SiO2)

Coal

Bituminous or sub-bituminous coal (carbonaceous rock)

Fossiliferous Limestone

Bioclastic Limestone (Calcium Carbonate, CaCO3)

Sandstone or Quartzite

Arenite (if sedimentary) / Quartzite (if metamorphic)

Sandstone (Glacial Cobble)

Arenite / Sedimentary Rock (primarily SiO2)

Quartzite Cobble

Metamorphosed Quartz Sandstone (SiO2)

Banded Gneiss / Veined Metamorphic Pebble

Metamorphic Rock with Quartz/Feldspar Veins

Granite with Cupules / Bedrock Mortars

Granite (felsic intrusive plutonic rock)

Gneiss Pebble

Gneiss

Greenish altered rock, possibly serpentinite or chlorite-rich schist

Tentative: serpentine-group minerals, chiefly antigorite/lizardite, or chlorite–actinolite assemblage

Red Sandstone

Arenite (Ferruginous Sandstone)

Granite

Granite

Granite fragment (tentative)

Granite; primarily quartz (SiO₂), feldspar, and mica

Granite / granitic gneiss boulders

Granite, primarily quartz, feldspar, and mica; some pieces may be foliated granitic gneiss

Light-colored granite or granitic gneiss

Granite; typically quartz + feldspar + mica (variable composition)

Painted River Rock

Painted Quartzite or Smooth Siltstone

Banded agate (likely botryoidal chalcedony)

Agate, microcrystalline quartz (SiO₂), commonly chalcedony with quartz bands

Sandstone with Iron Banding

Arenite with Hematite or Limonite staining (SiO2 with Fe2O3)

Quartz Geode

Silicon Dioxide (SiO2)

Fish Fossil in Limestone

Lycoptera (likely) in Micritic Limestone

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Sandstone (likely Greywacke or Lithic Sandstone)

Arenite / Wacke

Quartzite with Hematite staining

Quartzite (SiO2) with iron oxide inclusions

Halite

Sodium Chloride (NaCl)

Schist

Metamorphic Schist

Coal

Carbonaceous sedimentary rock / Lignite to Bituminous coal

Pyrite-bearing Rock / Pyrite Ore

Iron Sulfide (FeS2) in host rock matrix

Quartzite (River Pebble)

Meta-quartzite (composed primarily of SiO2)