Indeterminate

Likely fossilized shell or bone fragment

Indeterminate bioclast; possibly silicified/bioapatite-bearing shell or bone

Uncertain fine-grained rock or mineral-bearing specimen

Indeterminate; possible quartz- or feldspar-bearing matrix with reflective grains

Likely weathered iron-rich rock or mineral fragment

Indeterminate; possibly limonite/goethite-rich material with quartz or feldspar

Likely weathered brown rock or iron-rich mineral specimen

Indeterminate from image; possible limonite/goethite-rich material

Rounded gray river pebble

Indeterminate; likely weathered basalt, andesite, or fine-grained graywacke

Uncertain small tan mineral/rock fragment

Indeterminate from image; possibly feldspar-rich rock or calcite

Weathered quartz-rich rock, possibly chert or quartzite

Indeterminate; likely microcrystalline quartz (SiO₂), possibly quartzite or chert

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate, possibly altered granite

Small weathered pebble, possibly limestone

Indeterminate carbonate-rich rock; likely calcite-bearing limestone

Likely weathered river pebble

Indeterminate lithology; possibly fine-grained sandstone, siltstone, or chert

River Pebble (Greywacke / Basalt Pebble)

Indeterminate Rounded Pebble (composed of quartz, feldspar, or mafic minerals)

Fossilized turtle shell fragment

Testudines indeterminate; shell bone permineralized with silica/carbonate minerals

Tooth or bone fragment (likely animal tooth)

Indeterminate vertebrate tooth; possibly a small mammal or fish tooth

Polished river pebble

Indeterminate fine-grained fluvial clast, likely sandstone or chert

Likely rough mineral specimen (possibly mica-rich)

Indeterminate from the image; a mica such as muscovite or biotite is one possibility

Possible fossilized bone fragment

Indeterminate fossil bone; no species can be identified from this image

Weathered, iron-stained rock (likely metamorphic)

Indeterminate from photograph; possibly quartz-rich gneiss or schist

Small reddish-brown mineral fragment, likely quartz-bearing rock

Indeterminate; possibly iron-stained quartz or feldspar-rich stone

Small dark mineral/rock fragment

Indeterminate; possibly biotite-rich schist, graphite, or metallic sulfide

Quartz-rich sandstone or chert fragment

Indeterminate siliciclastic rock; likely quartz arenite or weathered chert

Rounded iron-rich stone or concretion

Indeterminate; possibly hematite-/goethite-bearing sandstone or an ironstone concretion

Rounded greenish river pebble

Indeterminate; possibly weathered greenstone, basalt, or serpentinized ultramafic rock

Weathered quartz-bearing rock fragment

Indeterminate; likely quartz-rich granite, gneiss, or pegmatitic rock

Unidentified pale mineral or rock surface

Indeterminate from image; possibly a small quartz or feldspar grain

Possible fossilized shell or fossil fragment

Indeterminate; possibly a small brachiopod or gastropod fossil in mineralized matrix

Rounded weathered stone

Indeterminate; likely a fine-grained mafic rock such as basalt or andesite

Likely weathered metamorphic rock (possibly schist or gneiss)

Indeterminate; probable mica-rich quartz–feldspar metamorphic rock

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate (SiO₂ with feldspar minerals)

Weathered sandstone or altered volcanic rock

Indeterminate; likely quartz–feldspar-rich sandstone, possibly tuff

Likely polished dark gemstone cabochon

Indeterminate; possibly black chalcedony/agate, obsidian, or glass imitation

Tumbled brown stone, possibly jasper or iron-rich chert

Indeterminate; likely microcrystalline quartz (SiO₂) with iron-oxide coloration

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz (SiO₂) with feldspar and minor dark minerals

Small metallic-looking mineral/rock fragment

Indeterminate from image; possibly galena, hematite, or metallic slag

Unidentified gray stone/concrete-like fragment

Indeterminate; likely a fine-grained carbonate or cementitious geological fragment

Fossilized shell or small fossil fragment

Indeterminate fossil; possibly a partial gastropod or bivalve, mineralized with calcite

Fossilized gastropod (snail)

Silicified or calcite-replaced gastropod fossil; exact genus indeterminate

Weathered brown rock fragment

Indeterminate; possibly iron-stained sandstone, mudstone, or weathered limestone

Weathered quartz-rich cobble, likely sandstone or quartzite

Indeterminate; probable quartz arenite (sandstone) or quartzite, dominated by SiO₂

Tiny rounded brown mineral grain

Indeterminate; possibly iron oxide, garnet, or a weathered sulfide grain

Small pale mineral/rock fragment

Indeterminate; possibly weathered quartz, calcite, or light-colored limestone

Likely galena-bearing ore or graphite-rich sulfide fragment

Indeterminate; possibly galena (PbS) with quartz, or graphite-rich schist

Fossilized bone fragment

Mineralized vertebrate bone, likely mammalian; exact taxon indeterminate