Indeterminate

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

Indeterminate from photograph; possible quartz/feldspar-bearing granitic pebble

Small weathered stone, possibly quartz-rich sandstone

Indeterminate siliciclastic rock; likely quartz-bearing sandstone or chert fragment

Tumbled pale feldspar-rich stone (likely granite or quartzite fragment)

Indeterminate; possible quartz–feldspar aggregate, commonly granite or feldspathic quartzite

Weathered metamorphic rock, possibly schist or gneiss

Indeterminate; likely quartz–feldspar–mica rock, potentially greenschist or gneiss

Weathered iron-rich stone, likely basalt or ironstone

Indeterminate; possibly vesicular basalt (plagioclase–pyroxene) or ferruginous sandstone/ironstone

Weathered fossil fragment, possibly bone

Indeterminate fossilized bone; likely mineralized vertebrate bone (apatite-rich)

Rounded river pebble, likely weathered sandstone or siltstone

Indeterminate clastic sedimentary rock; likely quartz-rich sandstone/siltstone

Rounded weathered stone, likely basaltic or volcanic rock

Indeterminate fine-grained mafic volcanic rock; possibly basalt or andesite

Tumbled pale brown stone, possibly petrified wood or chalcedony

Indeterminate from image; likely microcrystalline quartz (SiO₂) or silicified wood

Small rounded pebble, likely weathered sandstone or iron-rich rock

Indeterminate; possibly quartz-rich sandstone (SiO₂) with iron-oxide staining

Rounded gray river pebble, likely granite or gneiss

Indeterminate granitic rock; commonly quartz + feldspar + mica, possibly gneissic

Small weathered mineral/rock fragment

Indeterminate; possibly quartz-bearing feldspathic rock or calcite-rich specimen

Tumbled reddish-brown mineral or gemstone fragment

Indeterminate from image; possibly carnelian (microcrystalline quartz), jasper, or garnet

Rounded pale pebble, likely quartz-rich stone

Indeterminate; possibly quartzite, quartz-bearing granite, or calcite-rich limestone

Weathered metallic sulfide-bearing rock, possibly schist or gneiss

Indeterminate; likely mica-rich metamorphic rock with iron sulfides or magnetite

Rounded brown pebble

Indeterminate lithic clast; possibly weathered sandstone or iron-stained quartzite

Rounded gray river cobble, likely quartz-rich sandstone or weathered granite

Indeterminate; possible granitic or feldspathic cobble (quartz–feldspar–mica aggregate)

Polished fossil tooth or jaw fragment

Indeterminate vertebrate dental/bone fossil; likely mineralized enamel and dentine

Tumbled reddish-brown pebble

Indeterminate lithic fragment; possibly iron-stained quartzite, chert, or jasper

Fossil shell fragment, likely bivalve or gastropod

Indeterminate molluscan fossil; original shell likely aragonite or calcite (CaCO₃)

Rounded yellow-brown pebble, likely quartz-rich sandstone or chert

Indeterminate; possible quartz arenite (SiO₂-rich sandstone) or microcrystalline chert

Fossilized bivalve shell

Calcitic or aragonitic mollusk shell, commonly Bivalvia; exact species indeterminate

Polished brown pebble

Indeterminate; possibly jasper, iron-rich quartzite, or a weathered ironstone pebble

Tumbled iron-rich stone, possibly jasper or weathered basalt

Indeterminate; likely iron-stained microcrystalline quartz (jasper) or altered basalt

Unidentified small rock fragment

Likely quartz-rich material; exact identification is indeterminate from the image

Unknown dark mineral fragment

Indeterminate; possibly a dark silicate mineral or slag-like geological fragment

Weathered iron-rich rock, possibly limonite-bearing sandstone or altered volcanic rock

Limonite/goethite mixture; exact host rock is indeterminate from the image

Fossilized stromatolite or laminated microbial mat

Layered carbonate/chert fossil; exact taxon indeterminate from the image

Unidentified gray rock fragment

Indeterminate from image; possibly quartz- or feldspar-rich silicate material

Unidentified pale stone or mineral specimen

Indeterminate; possibly massive quartz, calcite, or a light-colored feldspathic rock

Likely polished brown quartz-rich stone

Indeterminate; possibly quartz-bearing jasper, agate, or iron-stained quartz

Possible weathered iron-rich rock or slag fragment

Indeterminate; likely limonite/goethite-bearing material, possibly iron slag

Weathered quartz-bearing rock, possibly gneiss or quartzite

Indeterminate; likely quartz-rich metamorphic rock containing quartz and feldspar

Weathered feldspathic rock, likely granite or granitic pegmatite

Quartz–feldspar–mica aggregate; exact species indeterminate from the image

Weathered brown stone, likely sandstone or iron-stained granite

Indeterminate; possible quartz-rich sandstone (quartz, feldspar, iron oxides)

Fossil-bearing ironstone or weathered concretion

Indeterminate; likely ferruginous sandstone/concretion containing a partial fossil impression

Likely weathered fossil bone fragment

Indeterminate fossilized bone; taxonomic identification requires microscopy and locality data

Likely vertebra fossil or bone fragment

Indeterminate fossilized vertebra; mineralized hydroxyapatite, commonly Ca₅(PO₄)₃(OH)

Rounded river pebble

Indeterminate; likely quartz-rich sandstone, chert, or weathered volcanic rock

Conical fossil shell or shell fragment

Likely a gastropod shell fragment; exact taxon indeterminate from the image

Weathered brown rock, likely sandstone or iron-rich quartzite

Indeterminate; probable quartz-rich sandstone (quartz, feldspar, iron oxides)

Weathered quartz-rich rock, possibly chert or quartzite fragment

Indeterminate; likely microcrystalline quartz (SiO₂), possibly with iron-oxide staining