Organic (Paper And Cellulose)

Limestone

Calcium Carbonate (CaCO3)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Likely galena-bearing ore or graphite-rich sulfide fragment

Indeterminate; possibly galena (PbS) with quartz, or graphite-rich schist

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Granite

Phaneritic intrusive igneous rock

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Pyrite

Iron Sulfide (FeS2)

Banded Agate (specifically shades of Carnelian Agate)

Silicon Dioxide (SiO2)

Polished fossiliferous limestone, likely crinoidal or coral limestone

Calcite (CaCO₃), fossiliferous carbonate rock

Polished purple banded agate geode

Cryptocrystalline quartz (chalcedony), SiO₂, with purple coloration likely from amethyst/quartz and possible dye enhancement

Polished banded metamorphic stone, likely gneiss or quartzite

Banded quartz–feldspar–mica rock; precise identification requires testing

Polished basalt with a quartz vein

Basalt, cut by milky quartz (SiO₂)

Rounded sandstone cobble

Quartz-rich sandstone, likely arkosic or lithic sandstone

Pyrite

Iron Disulfide (FeS2)

Porphyritic Basalt (Flowerstone)

Porphyritic Basalt (Mafic volcanic rock)

Porphyry

Porphyritic Andesite/Dacite

Pyrite

Iron Sulfide (FeS2)

Tumbled dark banded stone, possibly indigo gabbro or banded basalt

Indeterminate; likely fine-grained mafic rock composed mainly of plagioclase and pyroxene, with possible amphibole or alteration minerals

Conglomerate

Conglomeratic Sandstone / Polymictic Conglomerate

Smooth river pebble, likely quartz-rich sandstone or quartzite

Indeterminate quartz-rich clast; possibly quartzite (mostly SiO₂)

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

Anthracite coal

Anthracite; predominantly carbon (C), with minor mineral impurities

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 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 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 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

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)