Indeterminate

Porous sandstone or weathered limestone fragment

Indeterminate clastic carbonate/siliciclastic rock; likely quartz-rich sandstone or calcarenite

Weathered quartz-bearing rock, likely granite or granitic gneiss

Indeterminate granitic rock; chiefly quartz (SiO₂), feldspar, and dark mica/amphibole

Possible sandstone cobble or weathered basalt

Indeterminate lithic specimen; likely quartz-rich sandstone, possibly weathered basalt

Rounded brown pebble, likely weathered basalt or iron-rich chert

Indeterminate; possibly basalt (fine-grained mafic silicate rock) or ferruginous chert

Weathered porous sandstone or tuff

Indeterminate siliciclastic rock, likely quartz-rich sandstone; possibly volcanic tuff

Rounded quartz-rich pebble

Quartz-bearing lithic clast; exact rock type indeterminate from image

Unidentified rounded mineral/rock fragment

Indeterminate; likely a weathered quartz-rich stone or iron-stained granite fragment

Tumbled cream-colored pebble, likely quartz or calcite

Indeterminate from photograph; possibilities include microcrystalline quartz (SiO₂) or calcite (CaCO₃)

Blue cabochon gemstone, likely synthetic glass or dyed stone

Indeterminate from image; possible glass, synthetic spinel, sodalite, or lapis lazuli

Rounded brown-gray pebble, likely weathered basalt or iron-stained chert

Indeterminate from image; possible basalt (plagioclase–pyroxene) or chert (microcrystalline SiO₂)

Rounded river cobble, likely weathered sandstone or quartzite

Indeterminate clastic silicate rock; possibly quartz-rich sandstone (SiO₂-dominant)

Weathered granite pebble

Granite, predominantly quartz–feldspar–mica; exact variety indeterminate from the photo

Mixed weathered field rocks, likely sandstone and shale/slate

Indeterminate clastic rocks; possible quartz-rich sandstone with laminated shale or slate

Weathered brown stone, possibly mudstone or iron-stained limestone

Indeterminate sedimentary rock; likely clay-rich mudstone/shale or ferruginous limestone

Weathered iron-rich rock fragment

Indeterminate; likely limonite/goethite-bearing rock, possibly altered basalt or ironstone

Polished fossil shell or bone fragment (tentative)

Indeterminate biogenic carbonate or fossilized bone; possibly a small gastropod/bivalve fragment

Small rounded pebble, likely weathered sandstone or iron-stained sedimentary rock

Indeterminate; probable quartz-rich sandstone (SiO₂ with clay/iron-oxide cement)

Possible fossilized bone or tooth fragment

Indeterminate fossilized vertebrate material; mineralized hydroxyapatite replaced or coated by silica/carbonate

Banded river pebble, likely weathered sandstone or mudstone

Indeterminate lithic clast; probable quartz-rich sandstone or iron-stained mudstone

Fossilized bivalve shell

Indeterminate fossil mollusk; likely a brachiopod or bivalve, originally calcite/aragonite (CaCO₃)

Likely tumbled red mineral or glass imitation

Indeterminate; possibilities include red jasper (microcrystalline quartz, SiO₂) or dyed chalcedony

Fossil tooth or shell fragment (likely fossilized reptile/dinosaur tooth fragment)

Indeterminate vertebrate dental fossil; mineralized hydroxyapatite replaced or infilled by silica/carbonate

Fossilized shell, likely gastropod or bivalve

Recrystallized carbonate fossil; original shell likely aragonite or calcite (taxon indeterminate)

Small gray rock fragment

Indeterminate; possibly quartz-rich granite, chert, or concrete-like silicate material

Red/pink tumbled mineral fragment

Indeterminate; possibly dyed quartz, ruby/corundum, or red glass-like chalcedony

Weathered sandstone or siltstone exposure

Quartz–feldspar clastic sedimentary rock; exact lithology indeterminate from the image

Small marine shell fragment

Calcareous shell, primarily calcium carbonate (aragonite or calcite); exact taxon indeterminate

Fossilized vertebra, likely mammalian

Mineralized vertebral centrum and neural arch; exact taxon indeterminate from the image

Unidentified brown mineral/rock fragment

Indeterminate from image; possibly iron-stained quartz, feldspar, or weathered limonite

Weathered brown rock fragment

Indeterminate; possibly weathered granite, gneiss, or iron-stained quartz-rich rock

Weathered sandstone or quartz-rich rock fragment

Indeterminate siliciclastic sandstone; primarily quartz (SiO₂) with feldspar and iron-oxide cement

Weathered sandstone or volcanic rock fragment

Indeterminate; likely quartz–feldspar-rich sandstone, possibly altered volcanic rock

Rounded reddish-brown river pebble

Indeterminate weathered silicate rock, possibly granite, rhyolite, or iron-stained quartzite

Rounded river pebble

Indeterminate lithic clast; likely weathered sandstone or quartz-rich sedimentary rock

Rounded gray-brown river pebble

Indeterminate lithic clast; likely weathered sandstone or fine-grained metamorphic rock

Fossilized shell fragment

Indeterminate fossil mollusk; likely a silicified or mineral-replaced bivalve/gastropod fragment

Rounded beach pebble

Lithology indeterminate; likely fine-grained sandstone, mudstone, or weathered volcanic rock

Likely weathered quartz-rich stone or fossil fragment

Indeterminate; possibly quartz-bearing sandstone, iron-stained quartz, or a fragmentary fossil

Lichen-covered graywacke or granitic glacial cobble

Indeterminate; likely quartz–feldspar–mica rock, possibly weathered granite or granodiorite

Weathered quartz-rich stone, possibly fossiliferous limestone

Indeterminate; likely calcite-rich limestone (CaCO₃) or weathered quartz-bearing rock

Pink feldspar-rich rock, likely rose quartz or pink granite fragment

Indeterminate from image; possible potassium feldspar (orthoclase, KAlSi₃O₈) or quartz (SiO₂)

Rounded river pebble (lithology unclear)

Indeterminate natural rock; no specific mineral or rock type can be identified from the image