Organic (Paper And Cellulose)

Tumbled epidote-bearing granite or amphibolite

Quartz–feldspar rock with dark amphibole/biotite and epidote; exact identification is uncertain from the image

Pyrite

Iron Disulfide (FeS2)

Polished banded limestone or marble pebble

Calcite-rich carbonate rock; likely banded marble (recrystallized limestone)

Polished orbicular granite (likely larvikite-type stone)

Coarse-grained granitoid composed mainly of feldspar, quartz, and dark mafic minerals; exact variety is uncertain from the image

Agate

Silicon Dioxide (SiO2) - Banded Chalcedony

Granite (with Quartz and Mica)

Phaneritic Felsic Igneous Rock

Polished gray pebble

Likely quartz-rich chert or fine-grained quartzite; exact identification is uncertain from the photograph

Likely polished black stone, possibly obsidian

Obsidian (volcanic glass; primarily SiO₂), tentative identification

Quartzite

Quartzite (SiO2)

Polished agate geode slice

Banded chalcedony (microcrystalline quartz, SiO₂) with central quartz druse

Granite Cobble

Felsic intrusive igneous rock (composition: SiO₂ with KAlSi₃O₈, NaAlSi₃O₈, and CaAl₂Si₂O₈)

Polished black stone, likely basalt or volcanic glass

Basalt (fine-grained mafic rock) or, less likely, obsidian (volcanic glass)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Polished banded gneiss or amphibolite specimen

Biotite–quartz–feldspar gneiss, possibly amphibole-rich; exact identification requires testing

Tumbled yellow-green pebble, likely serpentine or quartzite

Provisional: serpentine-group rock, chiefly Mg₃Si₂O₅(OH)₄; exact identification requires testing

Conglomerate

Conglomerate (clastic sedimentary rock)

Pyrite

Iron Disulfide (FeS2)

Pyrite

Iron Sulfide (FeS2)

Polished blue-gray agate/geode slice (tentative)

Microcrystalline quartz (chalcedony), SiO₂, possibly with druzy quartz

Serpentinite

Serpentinite (composed mainly of serpentine group minerals: (Mg,Fe)3Si2O5(OH)4)

Tumbled beach pebble (likely quartz-rich sandstone or chert)

Indeterminate lithic clast; likely quartz (SiO₂)-rich sandstone/chert

Tumbled blue quartzite or blue chalcedony (uncertain)

Quartz-rich rock; predominantly silicon dioxide (SiO₂)

Moss agate (likely plume or dendritic agate)

Chalcedony, microcrystalline quartz (SiO₂), with iron-oxide inclusions

Pearl

Calcium carbonate (CaCO3) in the form of aragonite

Polished amber

Amber (fossilized plant resin; chiefly amorphous organic compounds)

Petrified Wood

Silicified wood (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified wood (SiO2)

Amber / Copal

Organic resin, C10H16O

Cat's Eye Operculum

Turbo petholatus operculum

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Pearl

Calcium Carbonate (Aragonite/Calcite) - CaCO3

Seashell Fragment

Calcium carbonate (CaCO3) - primarily Aragonite or Calcite

Red Coral

Corallium rubrum

Polished moss agate (likely)

Chalcedony, microcrystalline quartz (SiO₂), with dark mineral inclusions

Amber cabochon pendant

Amber (fossilized tree resin; chiefly polymerized terpenoids)

Polished/tumbled quartz-rich rock, possibly quartzite

Quartzite; predominantly crystalline SiO₂, with minor iron-oxide and other impurities

Agate (various color varieties)

SiO₂ (Silicon Dioxide)

Polished blue calcite sphere (tentative identification)

Calcite, CaCO₃; blue color generally results from trace impurities or inclusions

Polished white chalcedony or milky quartz pebble

Chalcedony, microcrystalline quartz (SiO₂), possibly with iron-oxide staining or a minor mineral inclusion

Pearl

Calcium Carbonate (Aragonite/Calcite) and Conchiolin