Indeterminate

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

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)

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

Blue-green tumbled stone, possibly turquoise

Unidentified opaque copper-bearing mineral; turquoise is a candidate (CuAl₆(PO₄)₄(OH)₈·4H₂O)

Rounded river pebble, likely fine-grained volcanic rock

Indeterminate from the image; possibly andesite or basalt

Small tan mineral or rock fragment (unidentified)

Indeterminate from the image; no diagnostic features are visible

Small rounded tan pebble, likely quartz-rich river stone

Indeterminate; possibly quartz or quartzite (predominantly SiO₂)

Banded dark pebble (likely gneiss or banded metamorphic rock)

Indeterminate from the image; possibly banded gneiss

Small rounded mineral/rock fragment

Indeterminate; possibly quartz-rich stone or feldspar

Tumbled brown translucent mineral fragment

Indeterminate; possibly quartz/chalcedony or weathered feldspar

Dark, weathered rock fragment (possibly basalt or iron-rich stone)

Indeterminate; possible basalt (plagioclase–pyroxene rock)

Weathered sandstone or quartz-rich sedimentary cobble

Indeterminate sandstone, likely arkose or quartz arenite

Small weathered rock fragment

Indeterminate; possibly limestone or altered volcanic rock

Small weathered rock fragment

Indeterminate; possibly granitic or altered feldspathic material

Small polished metallic mineral specimen

Indeterminate from image; possibly galena or hematite

Fossilized bivalve shell

Bivalvia indeterminate; likely a fossil clam or cockle

Rounded gray pebble, likely quartz-rich granite or gneiss

Indeterminate granitoid; commonly quartz + feldspar + mica

Rounded yellow-brown river pebble

Indeterminate lithology; possibly weathered sandstone or chert

Trilobite fossil

Fossilized trilobite; exact genus/species indeterminate

Weathered brown sandstone or quartzite cobble

Indeterminate sandstone; possibly quartz-rich quartzite

Weathered river cobble, likely quartzite or sandstone

Indeterminate; probable quartz-rich sandstone/quartzite

Small quartz-rich stone, possibly granite fragment

Indeterminate; likely quartz (SiO₂) with feldspar and/or mica

Fossil brachiopod shell

Indeterminate articulate brachiopod; possibly a terebratulid or rhynchonellid

Sandstone with Brachiopod Mold Fossil

Sedimentary rock (Sandstone) with indeterminate Brachiopod mold

Unidentified Dark Mineral or Rock

Indeterminate (Likely Silicon Dioxide or Carbon-based)

Likely tumbled gray-green stone

Indeterminate; possibly serpentinite, quartzite, or weathered basalt

Tumbled brown pebble

Indeterminate; likely quartz-rich sandstone or chert

Likely polished dark stone or glassy mineral bead

Indeterminate; possibly obsidian, hematite, or a dark agate