Indeterminate

Likely calcite or limestone fragment

Calcite (CaCO₃), possibly limestone dominated by calcite

Likely weathered jasper or iron-rich chert

Microcrystalline quartz (SiO₂), with iron-oxide staining

Likely tumbled white quartz or quartzite pebble

Quartz (SiO₂), possibly quartzite

Dark green mineral specimen, possibly serpentine or epidote

Tentatively serpentine-group mineral, Mg₃Si₂O₅(OH)₄, or epidote, Ca₂(Al,Fe)₃Si₃O₁₂(OH)

Fossilized bone fragment (probable large mammal bone)

Mineralized vertebrate bone; commonly hydroxyapatite, Ca₅(PO₄)₃(OH), partly replaced by silica or calcite

Pyrite-bearing rock (likely pyrite schist or pyritized shale)

Pyrite (FeS₂) in a fine-grained schistose or shale matrix

Weathered sandstone or siltstone

Clastic sedimentary rock, chiefly quartz and feldspar grains cemented by silica, iron oxides, or carbonate

Weathered conglomeratic or breccia cobble

Lithified polymictic conglomerate/breccia, likely iron-stained siliciclastic rock

Likely river-worn dark stone (possibly basalt or shale)

Indeterminate; likely fine-grained basalt (plagioclase–pyroxene), though slate/shale is also possible

Likely coral fragment or calcareous fossil

Aragonite/calcite (CaCO₃), possibly fossil coral such as Pocillopora or a bryozoan

Polished black stone, likely basalt or amphibolite

Basalt (fine-grained mafic rock), possibly amphibolite; primarily plagioclase and pyroxene/amphibole

Tumbled amber-colored pebble

Likely quartz/chert or iron-stained chalcedony; exact identification requires testing

Small rounded pale stone

Indeterminate; likely quartz-rich pebble, possibly quartz or light-colored feldspar

Weathered iron-rich rock fragment

Likely limonite/goethite-bearing rock, possibly altered pyrite or mica schist

Weathered iron-rich rock, likely ferruginous sandstone or lateritic concretion

Iron-oxide–cemented sandstone; commonly dominated by quartz (SiO₂), goethite (FeO(OH)) and hematite (Fe₂O₃)

Rounded sandstone cobble

Quartz-rich sandstone (likely arkose or litharenite)

Reddish-brown, iron-stained rock fragment

Indeterminate; possibly weathered porphyritic volcanic rock

Rounded quartz-rich pebble, possibly chert or quartzite

Indeterminate; likely microcrystalline quartz (SiO₂) or quartzite

Likely quartz-rich rock fragment

Indeterminate; possibly quartz-bearing granite or quartzite

Likely polished dark stone or mineral fragment

Indeterminate; possibly hematite, magnetite, or dark basalt

Probable iron-rich mineral or weathered rock fragment

Indeterminate; possibly limonite/goethite-bearing material

Rounded quartz-rich pebble

Chert or quartzite pebble (indeterminate from image)

Weathered sandstone or iron-rich sedimentary rock

Indeterminate siliciclastic sandstone, possibly ferruginous sandstone

Small weathered rock fragment

Indeterminate; possibly carbonate-rich sandstone or limestone

Fossilized ammonite

Ammonoidea (likely an ammonite; exact genus indeterminate)

Likely iron-rich rock or meteorite fragment

Indeterminate; possible hematite-/magnetite-bearing material

Weathered quartz-rich rock fragment

Indeterminate; likely quartz-bearing silicate rock

Probable weathered sulfide-bearing rock

Indeterminate; possibly pyrite- or chalcopyrite-bearing matrix

Weathered quartz-rich rock fragment

Indeterminate; likely quartz-bearing granitoid or quartzite

Rounded river pebble (likely weathered granite or metamorphic rock)

Indeterminate; possible granitic or quartz-rich lithology

White tumbled stone, likely quartz or calcite

Indeterminate; possibly quartz (SiO₂) or calcite (CaCO₃)

Possible fossilized shell or coral fragment

Indeterminate biogenic carbonate, likely calcite (CaCO₃)

Polished gray architectural stone panel

Indeterminate; likely polished granite or granitic gneiss

Fossilized bone or tooth fragment

Indeterminate fossil bone; possibly mammalian or reptilian

Small polished dark mineral specimen

Indeterminate; possibly black tourmaline (schorl) or hematite

Fossiliferous Sandstone / Fossil Fragment

Fossiliferous Sedimentary Matrix with Indeterminate Fossil Material

Fossiliferous Limestone / Fossil Fragment

Calcium Carbonate (CaCO3) with indeterminate biogenic remains

Rounded river pebble, likely quartz-rich sandstone or quartzite

Indeterminate quartz-rich clast; predominantly SiO₂

Weathered quartz-rich rock fragment

Indeterminate; possibly weathered granite, quartzite, or rhyolite

Banded metamorphic rock, likely gneiss or foliated amphibolite

Quartz–feldspar–mica gneiss or amphibolite; exact identification requires testing

Tumbled quartz-rich stone, possibly milky quartz or quartzite

Quartz (SiO₂), potentially quartzite (metamorphic rock)

Rounded green-gray river cobble

Likely altered basalt or andesite; exact identification requires a fresh surface and tests