Indeterminate

Orange chalcedony or tumbled carnelian fragment

Microcrystalline quartz (SiO₂), likely iron-stained chalcedony/carnelian

Weathered sandstone fragment

Quartz-rich clastic sandstone, possibly arkose or lithic sandstone

Rounded sandstone pebble

Quartz-rich sandstone, likely arkose or subarkose

Rounded quartz-rich pebble, likely quartzite or chert

Quartzite (mostly microcrystalline SiO₂); exact identification requires hardness and acid tests

Quartz-rich breccia or quartzite with iron-oxide veining

Microcrystalline to granular SiO₂ (quartz), with hematite/goethite and minor feldspar or mica

Amygdaloidal basalt pebble

Vesicular basalt, locally calcite- or quartz-filled amygdales

Weathered sandstone pebble

Quartz-rich sandstone, commonly arkosic or ferruginous sandstone

Iron-rich weathered pebble

Likely limonite/goethite-bearing rock; exact identification requires testing

Pearl

Pearl; primarily aragonite (CaCO₃) with conchiolin

Fossilized bivalve shell

Bivalvia indeterminate; likely a preserved clam or cockle shell, composed mainly of calcium carbonate (CaCO₃)

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

Fossil shell fragment

Indeterminate molluscan bioclast, likely aragonite or calcite

Pale green translucent mineral fragment

Indeterminate; possibly fluorite, calcite, or glassy quartz

Fossil-bearing sedimentary rock, possibly fossil wood or bone

Indeterminate silicified/carbonate fossil in sandstone or mudstone

Likely dark green-gray metamorphic pebble

Indeterminate; possibly chlorite schist, serpentinite, or amphibolite

Brown Pebble (River Rock)

Indeterminate (Likely Silicon Dioxide / Quartz-rich)

Likely tumbled quartz or feldspar fragment

Quartz (SiO₂) or feldspar-group silicate

Weathered quartz-rich pebble, possibly metasandstone

Quartz-rich metasandstone (provisional); mainly SiO₂ with minor feldspar, mica, or iron oxides

Rounded yellow-brown chert or jasper pebble

Microcrystalline quartz (SiO₂), likely iron-stained chert/jasper

Weathered quartz-rich metamorphic rock, likely quartzite

Quartzite, predominantly crystalline SiO₂, possibly micaceous or feldspathic

Polished turquoise-colored stone, likely chrysoprase or dyed agate

Uncertain; possible chalcedony (microcrystalline SiO₂) or turquoise (hydrous copper aluminum phosphate)