Organic (Paper And Cellulose)

Limestone

Calcium Carbonate (CaCO3)

Banded sandstone pebble

Lithified quartz–feldspar sandstone, possibly iron-oxide-banded arenite

Pyrite

Iron Disulfide (FeS2)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Pyrite

Iron Sulfide (FeS2)

Polished dark greenstone with quartz vein

Likely chlorite-rich metabasalt or greenschist with a quartz–feldspar vein

Polished black stone, likely basalt or black jasper

Indeterminate; possible fine-grained basalt (plagioclase–pyroxene) or black jasper/microcrystalline quartz

Polished green calcite (often sold as “onyx marble”)

Calcite, CaCO₃; banded crystalline limestone/travertine

Polished orbicular gabbro (likely “leopard-skin” or larvikite-type material)

Gabbro, a coarse-grained mafic plutonic rock; chiefly plagioclase feldspar and pyroxene, with possible olivine/amphibole and iron oxides

Limestone

Calcium Carbonate (CaCO3)

Pyrite (Fools Gold)

Iron Sulfide (FeS2)

Pyrite

Iron Sulfide (FeS2)

Polished tiger iron carving

Tiger iron, chiefly hematite–jasper–crocoite/goethite-rich ironstone; composition is uncertain from the image

Limestone

Calcium Carbonate (CaCO3)

Limestone (Brecciated/Recrystallized)

Calcium Carbonate (CaCO3)

Chinese Writing Stone

Porphyritic Basalt (or Andesite) with Feldspar inclusions

Likely galena-bearing ore or graphite-rich sulfide fragment

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

Weathered iron-stained quartzite or sandstone cobble

Quartzite, chiefly SiO₂, with iron-oxide staining; possibly ferruginous sandstone

Rounded quartz-rich river pebble

Likely quartz arenite or chert-derived sandstone; identification is limited from the photograph

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Tumbled red jasper

Microcrystalline quartz (chalcedony), predominantly SiO₂, colored by iron oxides

Rounded river pebble, likely weathered basalt or andesite

Fine-grained volcanic rock; composition commonly plagioclase, pyroxene, and minor iron oxides

Limestone

Calcium Carbonate (CaCO3)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Granite

Phaneritic intrusive igneous rock

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Banded Agate (specifically shades of Carnelian Agate)

Silicon Dioxide (SiO2)

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)

Pyrite

Iron Sulfide (FeS2)

Polished fossiliferous limestone, likely crinoidal or coral limestone

Calcite (CaCO₃), fossiliferous carbonate rock

Rounded sandstone cobble

Quartz-rich sandstone, likely arkosic or lithic sandstone

Pyrite

Iron Disulfide (FeS2)

Porphyritic Basalt (Flowerstone)

Porphyritic Basalt (Mafic volcanic rock)

Anthracite coal

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

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)