Organic (Paper And Cellulose)

Geode with Quartz and Chalcedony

Silicon Dioxide (SiO2)

Banded Iron Formation (Chert and Magnetite/Hematite)

Banded Iron Formation (BIF)

Tumbled cream-colored pebble

Likely quartz-rich sandstone or limestone; exact identification requires testing

Polished orbicular granite (likely leopard-skin granite)

Orbicular granite; quartz + feldspar + biotite/amphibole, with mafic orbicules

Aragonite (Banded Calcite / 'Mexican Onyx')

Aragonite (Calcium Carbonate - CaCO3)

Petoskey Stone

Hexagonaria percarinata

Tumbled agate or chalcedony

Microcrystalline quartz (SiO₂), likely gray-brown agate/chalcedony

Polished fossiliferous limestone (likely orbicular/fossil limestone)

Fossiliferous micritic limestone, composed primarily of calcite (CaCO₃)

Tumbled fossil coral (often sold as “petoskey stone” or fossil coral)

Fossilized colonial coral; commonly Hexagonaria percarinata in true Petoskey stones, though this specimen’s pattern may represent another fossil coral

Polished fossil shell fragment

Likely fossilized bivalve shell; mineralized aragonite/calcite (exact taxon indeterminate)

Red Jasper

Jasper (Silicon Dioxide with Iron Oxide inclusions, SiO2)

Granite Cobble

Granite

Polished black septarian nodule (likely septarian agate)

Septarian concretion composed mainly of microcrystalline quartz/chalcedony, dark calcite or aragonite, and brown iron-oxide mineralization

Dyed Agate Geode Slice

Silicon Dioxide (SiO2) - Banded Chalcedony

Tumbled brown agate

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide inclusions

Polished Septarian Nodule

Septarian calcite–aragonite concretion, commonly with barite or celestine

Agate Slice (Carnelian Agate)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Fossilized Coral (Petoskey-style)

Hexagonaria percarinata (Fossilized Rugose Coral)

Honey Calcite

Calcium Carbonate (CaCO3)

Chalk

Calcium Carbonate (CaCO3)

Diorite

Phaneritic intermediate plutonic rock

Rounded pebble, likely quartz-rich river stone

Indeterminate; possibly quartzite, chert, or a weathered quartz-feldspar rock

Rounded river pebble

Likely quartz-rich sandstone or weathered chert; exact identification requires testing

Polished orbicular granite (likely larvikite or granite egg)

Granite/larvikite; chiefly quartz, feldspar, and dark mafic minerals

Polished fossiliferous limestone

Fossiliferous micrite/bioclastic limestone, likely crinoidal or shell-rich limestone

Polished agate/geode slice

Microcrystalline quartz (chalcedony), mainly SiO₂, with possible calcite or quartz druse

Muscovite Schist with Quartz

Muscovite (KAl2(AlSi3O10)(OH)2) in Quartz Matrix

Limestone

Calcium Carbonate (CaCO3)

Clear Quartz (Facet Cut / Polished)

Silicon Dioxide (SiO2)

Tumbled amber-colored chalcedony

Chalcedony (microcrystalline quartz, SiO₂), possibly yellow jasper or resinous amber-colored agate

Likely graphite-rich schist or graphite-bearing metamorphic rock

Graphite (C) in a mica/quartz-rich matrix; exact rock name requires testing

Muscovite Mica (Golden/Yellow variety)

KAl2(AlSi3O10)(F,OH)2

Sandstone (with biological crust)

Arenite (SiO2 based)

Sandstone (likely Quartzose)

Sandstone (Principally SiO2)

Muscovite Mica (in Quartz matrix)

Potassium aluminum silicate hydroxide fluoride (KAl2(AlSi3O10)(F,OH)2)

Polished jasper pebble

Jasper, microcrystalline quartz (SiO₂) with iron-oxide and clay inclusions

Banded Agate

Cryptocrystalline Quartz (SiO2)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Sandstone (Pet Rock)

Clastic sedimentary rock (primarily SiO2)

Limestone

Calcite rock (CaCO3)

Garnet in Schist (Polished Tower)

Almandine Garnet (Fe3Al2(SiO4)3) in Mica Schist

Polished banded agate (likely sardonyx)

Cryptocrystalline chalcedony, SiO₂; reddish bands are iron-stained layers