Organic (Paper And Cellulose)

Muscovite Schist

Muscovite (KAl2(AlSi3O10)(OH)2) in Schist

Sandstone (with Iron Staining)

Quartz Arenite / Ferruginous Sandstone

Biotite Mica

Biotite (K(Mg,Fe)3AlSi3O10(OH,F)2)

Graphite-rich schist (probable)

Graphite schist; primarily graphite (C) with mica and quartz

Sandstone (Wonderstone)

Arenite (composed primarily of SiO2 with Fe2O3 impurities)

Banded Sandstone

Arenite with Liesegang banding (primarily SiO2 with FeO(OH) impurities)

Limestone

Limestone (CaCO3)

Kaolinite (Kaolin)

Kaolinite (Al2Si2O5(OH)4)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Rounded quartz-rich pebble

Likely quartzite or granitoid-derived felsic rock; exact identification is uncertain from the image

Petoskey Stone

Hexagonaria percarinata (Fossilized Rugose Coral)

Polished gray stone pebble

Likely fine-grained basalt or andesite; exact identification is uncertain from the photograph

Rounded gray river pebble

Likely fine-grained basalt or andesite; exact identification requires testing

Polished fossil ammonite cross-section

Ammonoidea (extinct cephalopod; commonly Jurassic/Cretaceous ammonite)

Pyrite (Fool's Gold)

Iron Pyrite (FeS2)

Polished red jasper (likely brecciated jasper)

Jasper, microcrystalline quartz/chalcedony; primarily SiO₂ with iron-oxide coloring

Banded Agate (specifically Carnelian Agate)

Silicon Dioxide (SiO2)

Petoskey Stone (Fossilized Rugose Coral)

Hexagonaria percarinata

Quartzite River Cobble

Quartzite (dominated by SiO2)

Marble

Metamorphosed Limestone (principally CaCO3)

Tumbled orbicular jasper

Orbicular jasper, chiefly microcrystalline quartz (SiO₂) with iron oxides and other silicates

Polished fossiliferous limestone (likely crinoidal or shell-rich limestone)

Bioclastic limestone, primarily calcite (CaCO₃), containing fossil fragments

Weathered river cobble, likely basaltic or andesitic volcanic rock

Fine-grained mafic to intermediate igneous rock; exact identification requires testing

Tumbled agate/chalcedony

Microcrystalline quartz (SiO₂), likely agate or jasper-bearing chalcedony

Amethyst geode

Quartz (SiO₂), purple variety colored mainly by iron and irradiation

Polished septarian nodule

Septarian concretion, commonly calcite-filled cracks in a claystone or limestone matrix

Weathered iron-rich rock, possibly ironstone or altered basalt

Indeterminate; likely ferruginous basalt/ironstone containing hematite-goethite and silicate minerals

Tumbled brown agate or jasper

Microcrystalline quartz, SiO₂, likely chalcedony with iron-oxide inclusions

Rounded granite cobble

Granite; predominantly quartz, alkali feldspar, plagioclase, and mica

Tumbled banded agate

Agate, microcrystalline chalcedony (SiO₂)

Polished/tumbled agate or jasper

Cryptocrystalline quartz, SiO₂; likely mossy or dendritic agate/jasper variety

Blue agate slice

Microcrystalline quartz (chalcedony), SiO₂, commonly colored blue by dyes or inclusions

Polished brecciated jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), with iron-oxide-rich breccia fragments and cement

Tumbled brown agate/chalcedony (probable)

Microcrystalline quartz, SiO₂; likely iron-stained agate or jasper

Polished porphyritic volcanic pebble

Likely porphyritic basalt or andesite; exact identification requires a fresh surface and mineral tests

Tumbled agate (likely Botswana or fortification agate)

Microcrystalline quartz, SiO₂ (chalcedony with banded impurities)

Banded Gneiss

Gneiss (quartz-feldspar-biotite metamorphic rock)

Puddingstone (Conglomerate)

Conglomerate (clastic sedimentary rock)

Tumbled banded stone, likely gneiss or granite

Quartz–feldspar rock, possibly banded gneiss; exact identification requires testing

Polished basalt or basaltic river pebble

Basalt; fine-grained plagioclase–pyroxene rock, possibly containing olivine

Red jasper pebble

Microcrystalline quartz (SiO₂), colored chiefly by iron oxides

Limestone

Sedimentary Rock (Primarily Calcite: CaCO3)