Unknown (Likely Sedimentary Or Metamorphic)

Rounded river pebble (lithology unclear)

Indeterminate natural rock; no specific mineral or rock type can be identified from the image

Greenish rough stone, possibly serpentine or soapstone

Indeterminate from the image; possible serpentinite (serpentine-group minerals) or talc-rich soapstone

Weathered iron-rich concretion or sedimentary rock

Likely ferruginous sandstone or ironstone concretion; exact identification is not possible from the image alone

Small yellow-brown stone, possibly iron-stained quartz or chert

Undetermined; visual evidence is insufficient for a confident identification

Likely quartzite

Quartzite, composed predominantly of quartz (SiO₂)

Polished dark stone, possibly black tourmaline or a dark pebble

Undetermined; image lacks detail for reliable identification

Likely mica-rich schist

Mica schist, probably muscovite/biotite-bearing quartz schist

Rounded river pebble, likely quartz-rich sandstone

Quartz-rich sandstone (tentative; exact identification is limited from the image)

Mottled rounded stone, possibly a weathered concretion

Unidentified lithic pebble; composition cannot be determined from the photograph

Tumbled orange-brown stone, possibly quartzite or jasper

Undetermined; likely iron-stained quartz-rich rock (quartz, SiO₂)

Small pale stone, possibly limestone

Unidentified carbonate rock; calcite-rich limestone is one possibility

Weathered, iron-stained rock fragment

Unidentified iron-oxide-stained silicate rock; precise identification is not possible from the image

Reddish-brown weathered rock (specific type uncertain)

Possibly iron-oxide-stained sandstone or siltstone; image alone is insufficient for a firm identification

Crushed stone aggregate

Mixed lithic aggregate; individual fragments cannot be identified from the image

Unidentified small rounded mineral/rock fragment

Indeterminate from image; possibly quartz or chalcedony with iron-oxide staining

Tiny amber-colored crystal fragment

Indeterminate; possibly quartz, feldspar, mica, or a sulfide mineral

Likely water-worn bone or fossil fragment

Indeterminate fossilized bone; species and age cannot be determined from the image

Green-tumbled stone, possibly epidote-bearing rock

Undetermined green silicate; possible epidote (Ca₂Al₂Fe³⁺(SiO₄)(Si₂O₇)O(OH)) in a rock matrix

Quartz vein in host rock

Quartz (SiO₂) vein cutting an unidentified, likely metamorphic host rock

Possible fossil-bearing pebble

Unidentified fine-grained sedimentary rock; the small orange feature may be a fossil or mineral inclusion

Likely halite (rock salt)

Halite, NaCl

Likely quartz-rich pebble

Quartz-bearing granite, granitic gneiss, or quartzite (indeterminate from photo)

Rounded beach or river pebble

Unidentified fine-grained rock; composition cannot be determined from the image

Rounded river pebble

Unidentified lithic pebble; exact rock type cannot be determined from the image

Blue-stone ring, likely set with blue glass or a dark-blue gemstone

The stone cannot be identified reliably from the image; possible sapphire (corundum, Al₂O₃), lapis lazuli, or glass

Weathered, garnet-bearing schist (tentative identification)

Mica schist, likely quartz–feldspar–mica schist; exact minerals cannot be confirmed from the photograph

Pyrite-bearing dark slate or phyllite

Likely pyrite (FeS₂) disseminated in fine-grained slate/phyllite; exact host rock cannot be confirmed from the photo

Tumbled pale greenish stone, likely serpentine or altered limestone

Probable serpentine-group rock (antigorite/lizardite), possibly serpentinite; identification is visual only

Possible dark cobble or pebble

Unidentified rock; composition cannot be determined from the image

Rounded gray-brown river pebble

Indeterminate lithic clast; likely weathered sandstone or fine-grained metamorphic rock

Likely serpentine or serpentinite

Serpentine-group minerals, chiefly antigorite, lizardite, or chrysotile; approximate formula Mg3Si2O5(OH)4

Likely iron sulfide specimen (pyrite or marcasite)

Pyrite, FeS₂; possibly marcasite, also FeS₂

Small brown mineral fragment

Unidentified; the image lacks enough detail for a reliable species-level identification

Rounded pebble, likely fine-grained river stone

Unidentified lithic pebble; composition cannot be determined from the image

Dark gray river pebble

Undetermined fine-grained mafic or intermediate rock; composition cannot be identified reliably from the image

Likely iron-rich metamorphic rock (possibly hematite-rich ironstone)

Unidentified ferruginous rock; exact mineralogy cannot be determined from the image

Small metallic-looking rock fragment

Uncertain; possibly galena-bearing ore or mica-rich schist

Likely sandstone pebble

Quartz-rich sandstone (composition uncertain from the image)

Sandstone or Quartzite with algae

Unknown specific, largely SiO2 with biological growth

Quartz-rich mica schist (tentative)

Quartz–muscovite/biotite schist; exact identification requires closer examination

Tumbled feldspar-rich rock, possibly granite or gneiss

Indeterminate feldspar–quartz rock; exact identification requires testing

Iron-stained quartz-rich rock

Quartz-rich vein rock, possibly iron-oxide-stained quartzite or brecciated quartz