Organic (Paper And Cellulose)

Banded iron formation (specimen, possibly hematite–jasper)

Banded iron formation; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and silica (chert/quartz), with possible limonite/goethite staining

Tumbled greenish chalcedony or serpentine pebble

Likely microcrystalline quartz (chalcedony, SiO₂) or serpentine-group mineral; exact identification requires testing

Tumbled banded agate

Agate, microcrystalline quartz (SiO₂), commonly chalcedony with iron-oxide inclusions

Tumbled banded agate

Chalcedony (microcrystalline quartz), SiO₂

Tumbled pegmatitic rock, likely amazonite-bearing granite

Granite/pegmatite composed mainly of quartz, feldspar, and mica; blue-green area may be microcline (amazonite)

Polished chalcedony (likely sagenite or included agate)

Microcrystalline quartz, SiO₂, with iron-oxide and possibly rutile/goethite inclusions

Polished fossiliferous limestone, possibly ammonite-bearing

Calcite-rich limestone (CaCO₃), with visible fossil or shell fragments

Quartz geode slice

Microcrystalline and crystalline quartz, silicon dioxide (SiO₂)

Polished agate geode slice

Quartz (SiO₂), chiefly chalcedony with drusy crystalline quartz; likely an agate geode

Fossil Coral (Petoskey Stone / Rugose Coral)

Hexagonaria percarinata (or similar fossilized rugose/tabulate coral)

Tumbled orbicular granite or granitic gneiss

Granite, chiefly quartz–feldspar–biotite/amphibole; exact variety uncertain from the image

Black polished/tumbled stone, likely basalt or black jasper

Most likely fine-grained basalt (plagioclase and pyroxene); appearance can also match microcrystalline quartz (black jasper)

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Petoskey Stone

Hexagonaria percarinata (Fossilized Rugose Coral)

Banded Agate (specifically Sardonyx or Carnelian Agate)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Dyed and polished agate pebble

Microcrystalline quartz (SiO₂), likely chalcedony/agate with blue dye

Graphitic schist (likely carbonaceous slate)

Graphite-bearing pelitic schist; mainly quartz, mica, feldspar, and graphite

Slate

Foliated metamorphic rock

Banded Agate

Silicon Dioxide (SiO2)

Slate

Slate (Foliated metamorphic rock consisting mainly of quartz and muscovite or illite)

Calcite (Iceland Spar)

Calcite (Calcium Carbonate, CaCO3)

Slate River Stone

Foliated Metamorphic Rock (composed of illite, chlorite, and quartz)

Red Sandstone

Arenite (Ferruginous Sandstone)

Sandstone (Ferruginous)

Arenite with Iron Oxide (Limonite/Hematite) coating

Desert rose

Gypsum (selenite), CaSO₄·2H₂O, commonly forming rosette aggregates

Glauconite Siltstone

Glauconitic siltstone / K(Fe,Al,Mg)2[(Si,Al)4O10](OH)2

Rounded gray pebble, likely basalt or andesite

Fine-grained mafic to intermediate volcanic rock; commonly plagioclase with pyroxene and/or olivine

Polished/tumbled light-colored stone, possibly quartzite or marble

Uncertain; likely quartzite (mostly SiO₂) or calcite marble (CaCO₃)

Tumbled yellow chalcedony or calcite

Cryptocrystalline quartz (SiO₂), possibly yellow chalcedony; an alternative is yellow calcite (CaCO₃)

Painted Sandstone Cobble

Clastic Sedimentary Rock (Sandstone base)

Polished ironstone concretion with quartz/iron-oxide vein

Goethite–hematite-rich ironstone concretion, likely veined by quartz or chalcedony

Banded Sandstone (Zebra Stone)

Arenite with Iron Oxide Banding (Liesegang rings)

Chalk

Calcium Carbonate (CaCO3)

Marble

Recrystallized Calcite (CaCO3) / Marble

Banded Agate (Dyed Purple)

Agate (Variety of Chalcedony/Quartz), SiO2

Yellow Banded Agate

Silicon Dioxide (SiO₂)

Banded Iron Formation / Chert with Quartz Veining

Banded Iron Formation (BIF) / Cryptocrystalline Quartz (SiO2)

Septarian Nodule

Septarian concretion (Complex mixture of Siderite, Calcite, and Aragonite)

Tumbled milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Polished brecciated jasper (likely septarian or iron-rich jasper)

Microcrystalline quartz (chalcedony), SiO₂, with iron oxides and possibly calcite or other rock fragments

Banded Iron Formation (BIF) / Jaspilite

Banded Iron Formation (predominantly Hematite, Magnetite, and Quartz/Jasper)

Fossil Coral (Petoskey Stone / Favosites / Charlevoix Stone)

Hexagonaria percarinata / Favosites (Cnidaria)