Uncertain

Weathered limestone fragment

Limestone, predominantly calcite (CaCO₃)

Polished serpentine-rich stone (likely serpentine jasper or “rainforest jasper”)

Serpentine-group minerals, chiefly antigorite/lizardite, with iron oxides and silica-rich rock matrix

Weathered granite or granitic gneiss

Granite; chiefly quartz, feldspar, and mica

Weathered porphyritic volcanic rock (likely basaltic andesite)

Porphyritic basaltic andesite; mineral assemblage likely plagioclase, pyroxene, and iron oxides

Likely weathered mica schist fragment

Mica schist, chiefly muscovite/biotite mica with quartz and feldspar

Quartz-rich metamorphic rock, likely mica schist or quartzite

Quartz (SiO₂) with mica, feldspar, and possibly iron-oxide staining

Weathered sandstone or quartz-rich metasedimentary pebble

Likely quartz arenite (sandstone), possibly weakly metamorphosed; predominantly SiO₂ quartz with feldspar and iron-oxide cement

Amethyst (rough crystal cluster)

Quartz, SiO₂; purple coloration commonly caused by trace iron and natural irradiation

Tumbled dark stone, likely basalt or basaltic rock

Fine-grained mafic volcanic rock; commonly basalt, composed chiefly of plagioclase and pyroxene with possible olivine and iron oxides

Rounded river pebble, likely weathered quartzite or sandstone

Quartzite (mostly SiO₂), possibly ferruginous sandstone

Quartz-rich gneiss

Banded quartz–feldspar–mica gneiss

Likely petrified wood or silicified fossil fragment

Silicified wood; predominantly microcrystalline quartz (SiO₂)

Granite (likely weathered, quartz-rich granite)

Granite, a coarse-grained felsic intrusive igneous rock composed mainly of quartz, feldspar, and mica

Weathered granite fragment

Granite, a coarse-grained felsic intrusive igneous rock; likely quartz, feldspar, and mica

Rounded quartzite pebble

Quartzite, composed predominantly of quartz (SiO₂)

Quartz–feldspar pegmatite

Granitic pegmatite, chiefly quartz (SiO₂), feldspar, and mica

Porphyritic granite

Porphyritic granitoid, composed mainly of quartz and feldspar with dark mica or amphibole

Polished multicolored stone bead bracelet

Likely dyed or treated agate/jasper, chiefly microcrystalline quartz (SiO₂)

Blue glass-like gemstone, likely synthetic spinel or glass

Uncertain; possibilities include synthetic cobalt-blue spinel (MgAl₂O₄) or cobalt-colored glass

Quartz-rich granite or granitic pegmatite fragment

Granite, chiefly quartz (SiO₂), feldspar, and minor mica

Tumbled green aventurine (likely)

Quartz, SiO₂, with fuchsite or other green inclusions

Likely basalt

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine

Clear quartz crystal (likely)

Quartz, silicon dioxide (SiO₂)

Likely milky quartz with iron-oxide inclusions

Quartz, silicon dioxide (SiO₂)

Purple fluorite specimen

Fluorite (calcium fluoride, CaF₂)

Amber (likely rough amber)

Fossilized tree resin; composition varies, commonly rich in polymerized terpenoids

Orange halite (rock salt)

Halite, sodium chloride (NaCl)

Smooth, water-worn pebble (likely quartzite)

Quartzite, composed predominantly of recrystallized quartz (SiO₂)

Slate

Slate; fine-grained metamorphic rock composed mainly of clay minerals, mica, and quartz

Polished copper-bearing rock, likely cuprite-rich copper ore

Cuprite (Cu₂O) with native copper and iron-oxide matrix, probable

Milky quartz

Quartz (silicon dioxide, SiO₂)

Polished green aventurine (likely)

Quartz aggregate, SiO₂, with green fuchsite mica inclusions

Possible iron-stained chert (flint)

Microcrystalline quartz (SiO₂), likely colored by iron oxides

Raw honey calcite (likely)

Calcite, CaCO₃

Clear quartz crystal pendant

Quartz (silicon dioxide, SiO₂)

Likely amazonite-bearing feldspar specimen

Amazonite, a green variety of microcline feldspar (KAlSi₃O₈), with pale feldspar or quartz matrix

Chalcedony (possibly agate)

Microcrystalline quartz, SiO₂; agate is banded chalcedony

Weathered quartzite pebble

Quartzite, composed predominantly of SiO₂ (quartz)

Clear quartz crystal

Quartz (silicon dioxide, SiO₂)

Likely black tourmaline (schorl)

Schorl, NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

Purple quartz-bearing rock, likely amethyst-bearing quartzite or pegmatitic quartz

Quartz (SiO₂), with iron-related purple coloration; possible feldspar and mica impurities

Small native-gold specimen (possible gold-bearing rock)

Native gold, Au; exact identification cannot be confirmed from the image