Indeterminate

Rounded weathered stone, likely sandstone or chert

Indeterminate; probable quartz-rich clastic rock (sandstone) or microcrystalline silica (chert)

Likely tumbled green mineral (possibly serpentine or aventurine)

Indeterminate; possibilities include serpentine-group minerals, nephrite, or green aventurine quartz

Weathered mineralized rock fragment

Indeterminate; likely quartz–feldspar-rich lithic material with iron-oxide staining

Possibly tumbled dark stone or mineral specimen

Indeterminate from image; possibly black tourmaline, basalt, or another dark silicate

Likely weathered quartz-rich rock or mineral fragment

Indeterminate from image; possibly quartz-bearing pegmatite or iron-stained quartz

Likely weathered igneous rock fragments

Indeterminate; possibly basaltic or granitic rock with quartz, feldspar, and dark mafic minerals

Unidentified dark mineral/rock fragment

Indeterminate; appearance may fit a sulfide-bearing rock or iron-rich mineral

Weathered igneous rock fragment, possibly granite or granitic gneiss

Indeterminate; likely quartz–feldspar–mica aggregate (granite), possibly foliated gneiss

Weathered brown stone, likely sandstone or mudstone

Indeterminate clastic sedimentary rock; likely quartz-rich sandstone or lithified mudstone

Fossil shell fragment, likely brachiopod or bivalve

Indeterminate fossilized marine mollusk or brachiopod; mineralized calcite shell in a carbonate matrix

Polished/tumbled quartz-rich pebble, possibly jasper or quartzite

Indeterminate; likely microcrystalline quartz (SiO₂), potentially iron-stained jasper or quartzite

Small rounded pebble, likely quartz-rich stone

Indeterminate from photograph; possibly microcrystalline quartz (SiO₂) or a weathered silicate pebble

Tumbled brown-and-white feldspar-rich stone, likely granite or quartzite

Indeterminate; probably quartz–feldspar aggregate (granite) or quartzite, with iron-oxide staining

Tumbled gray feldspar-rich stone, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate, potentially fine-grained granite or quartzite

Weathered quartz-rich rock, possibly sandstone or quartzite

Indeterminate; likely quartz sandstone (SiO₂-rich), possibly weakly metamorphosed quartzite

Weathered fossiliferous limestone or fossil fragment

Indeterminate bioclastic carbonate rock; likely calcite (CaCO₃) with fossil shell material

Weathered sandstone or siltstone boulder

Indeterminate clastic sedimentary rock, likely quartz-rich sandstone (SiO₂-dominant)

Unidentified small stone fragments

Indeterminate; the image does not show enough detail to identify a mineral or rock species

Tumbled brown feldspar-rich rock, possibly tiger’s-eye or brecciated quartz

Indeterminate from image; likely quartz (SiO₂) with iron-stained feldspar or amphibole

Probable weathered sandstone or iron-rich sedimentary rock

Indeterminate siliciclastic rock; likely quartz-rich sandstone with iron-oxide staining

Small rounded pebble, likely quartz-rich stone

Indeterminate; possibly quartzite or light-colored granitoid, composed mainly of quartz and feldspar

Weathered fossiliferous limestone, likely coral or shell fragment

Calcite (CaCO₃), biogenic limestone; exact fossil taxon indeterminate from the image

Likely fossilized bone or tooth fragment

Indeterminate fossil bone; mineral replacement commonly calcite, silica, or iron oxides

Rounded river pebble, likely quartz-rich chert or fine-grained sandstone

Indeterminate lithic clast; possible microcrystalline quartz (chert) or quartz-rich sandstone

Tumbled brown stone, likely basalt or iron-stained quartzite

Indeterminate from photograph; possible basalt (mafic silicate rock) or quartzite (SiO₂)

Weathered iron-rich stone, possibly chert or quartzite

Indeterminate; likely silica-rich rock with iron-oxide staining (SiO₂-dominant)

Blue-gray mineral/rock fragment

Indeterminate; possibly azurite-bearing material, blue chalcedony, or dyed/coated stone

Yellow quartz-bearing rock, possibly sulfur-stained quartz or calcite

Indeterminate; likely quartz (SiO₂) and/or calcite (CaCO₃) with yellow iron/sulfur staining

Weathered sandstone or siltstone pebble

Indeterminate siliciclastic sedimentary rock, likely quartz-rich sandstone (SiO₂-dominated)

Fossilized tooth or jaw fragment (likely fish or reptile)

Indeterminate vertebrate bone/tooth; mineralized hydroxyapatite, commonly Ca₅(PO₄)₃(OH)

Polished metallic ore/mineral specimen, possibly pyrite-bearing schist

Indeterminate from image; likely pyrite (FeS₂) with quartz and/or mica in a metamorphic matrix

Weathered iron-rich rock, possibly ironstone or altered basalt

Indeterminate; likely ferruginous basalt/ironstone containing hematite-goethite and silicate minerals

Rounded gray-brown pebble

Indeterminate; likely weathered quartz-rich sandstone or fine-grained volcanic rock

Unidentified gray mineral/rock fragment

Indeterminate from image; possibly quartz-rich material or mica-bearing schist

Iron-rich reddish rock, possibly weathered basalt or ironstone

Indeterminate; likely oxidized mafic rock containing iron oxides and silicate minerals

Weathered brown rock, likely sandstone or iron-rich sedimentary stone

Indeterminate siliciclastic rock; likely quartz-rich sandstone with iron-oxide cement

Weathered sandstone or iron-rich sedimentary rock

Indeterminate siliciclastic rock; likely quartz-rich sandstone with iron-oxide staining

Polished gray stone, likely labradorite or gneiss

Indeterminate from image; possibly plagioclase-rich gneiss or labradorite-bearing rock

Weathered fossil shell or crinoid fragment

Likely fossilized echinoderm or bivalve fragment; exact taxon indeterminate from the image

Possible weathered sandstone or iron-rich sedimentary rock

Indeterminate siliciclastic rock; likely quartz-rich sandstone with iron-oxide cement

Possible fossil tooth or bone fragment

Indeterminate fossilized vertebrate material; species cannot be identified reliably from this image

Quartz-rich rock fragment, possibly granite or quartzite

Indeterminate quartz-bearing silicate rock; likely quartz (SiO₂) with feldspar and/or mica