Undetermined

Black faceted gemstone, possibly black spinel or onyx

Undetermined; candidates include spinel (MgAl₂O₄) or chalcedony (SiO₂)

Rounded gray pebble (likely fine-grained volcanic or sedimentary rock)

Undetermined from image; possibly andesite or a fine-grained sandstone

Small pale-green stone, possibly serpentine or quartz

Undetermined from the image; no diagnostic features confirm a specific mineral

Rounded purple-gray pebble

Undetermined fine-grained volcanic rock; possibly andesite or basalt

Iron-rich meteorite candidate

Undetermined; possible stony-iron or iron-oxide-rich meteorite

Dark weathered metamorphic rock, likely schist or phyllite

Undetermined; probably mica-rich quartz–feldspar schist/phyllite

Small dark metallic-looking rock fragment

Undetermined; possibly iron oxide-rich material or a metallic mineral

Fossil-bearing limestone with a gastropod fossil

Gastropod fossil in calcitic limestone (Gastropoda; exact species undetermined)

Small dark rock fragment, possibly shale or slate

Undetermined fine-grained silicate rock; visual identification is inconclusive

Possible basalt or other dark volcanic rock

Undetermined fine-grained mafic volcanic rock; basalt is a possibility

Rounded yellow stone, possibly iron-stained chert or quartzite

Undetermined from image; likely microcrystalline quartz (SiO₂) if chert

Dark gray rock fragment (unidentified)

Undetermined; the image does not show enough detail for reliable identification

Iron-stained quartz vein rock

Quartz (SiO₂) with iron-oxide staining; host rock undetermined

Weathered light-colored rock fragment, possibly quartz-rich rock

Undetermined; appearance may be quartzite or a quartz-rich granite fragment

Small brown stone, possibly a weathered quartz-rich pebble

Undetermined; the image does not show enough detail for a reliable identification

Small brown mineral fragment, possibly amber-colored quartz or chalcedony

Undetermined from image; quartz/chalcedony (SiO₂) is one possibility

Unidentified small brown rock

Undetermined; image does not show enough detail for reliable identification

Possibly tumbled black stone (uncertain; may be black glass or obsidian)

Undetermined; possible obsidian (natural volcanic glass, predominantly SiO₂)

Small dark rock fragment (unidentified)

Undetermined; the image does not show enough detail for reliable identification.

Green-gray stone pebble (not reliably identifiable from the image)

Undetermined; possibly a fine-grained sedimentary rock such as mudstone or siltstone

Yellow-green faceted gemstone (possibly peridot)

Undetermined; peridot is gem-quality olivine, (Mg,Fe)₂SiO₄

Small blue cut gemstone, possibly synthetic spinel or glass; species cannot be determined from the photo

Undetermined; blue synthetic spinel (MgAl₂O₄) is one possibility

Likely polished or naturally smoothed pebble with a pale mineral patch

Undetermined; possibly a dark volcanic rock with a quartz or feldspar inclusion

Small brown mineral or rock fragment

Undetermined; the image does not show enough detail for reliable identification

Likely polished dark stone or mineral specimen (unidentifiable from image)

Undetermined; possibly dark quartz-rich material, basalt, or obsidian

Likely metallic meteorite fragment

Undetermined iron or stony-iron meteorite; mineralogy requires testing

Possible iron-rich meteorite fragment

Undetermined; possible stony-iron or iron-oxide-rich meteorite

Small brown mineral fragment (undetermined)

Unidentified; image detail is insufficient for a reliable species identification

Likely metamorphic rock (possibly gneiss or schist)

Undetermined foliated metamorphic rock; exact identification requires closer examination

Small gray rock fragment, possibly limestone or marl

Undetermined carbonate-rich sedimentary rock; composition cannot be confirmed visually

Possible dark garnet or other rough mineral fragment

Undetermined; the image does not show enough diagnostic detail to identify a species

Small white shell fragment

Calcium-carbonate shell, likely aragonite or calcite; exact organism undetermined

Unidentified small rock fragment

Undetermined; the photo does not show enough detail for reliable mineral identification.

Tumbled gray-green stone, possibly labradorite

Undetermined; labradorite is a plagioclase feldspar, (Na,Ca)(Al,Si)₄O₈

Tumbled, mottled stone (possibly jasper or another ornamental rock)

Undetermined from the photograph; visual appearance is insufficient for a reliable species identification

Faceted yellow gemstone (possibly citrine or synthetic glass)

Undetermined; citrine is yellow quartz (SiO₂), but the image cannot confirm the material

Polished black stone, possibly obsidian

Undetermined; if obsidian, natural volcanic glass (silica-rich, chiefly SiO₂)

Blue-green faceted pendant stone

Undetermined; possibly synthetic glass or a blue-green gemstone such as topaz or quartz

Tumbled white stone beads, likely marble or quartz

Undetermined; possibly marble (recrystallized calcite, CaCO₃) or milky quartz (SiO₂)

Small brown pebble (likely iron-stained quartz or chert)

Undetermined silicate pebble; possible quartz (SiO₂) or chert (microcrystalline SiO₂)

Possible meteorite fragment

Undetermined; likely an iron-rich meteorite or meteorite-like slag fragment

Likely polished dark stone (identity uncertain)

Undetermined; possibly polished basalt, chert, or another dark silicate rock