Organic (Paper And Cellulose)

Rounded weathered stone

Indeterminate; likely a fine-grained mafic rock such as basalt or andesite

Dyed druzy agate/geode (likely dyed quartz)

Quartz, SiO₂, lining a chalcedony geode; vivid pink color appears artificially dyed

Polished fossil coral (likely agatized coral)

Fossilized colonial coral; commonly silicified as chalcedony/quartz (SiO₂)

Tumbled agate or chalcedony

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

Slate

Foliated Metamorphic Rock

Graphitic schist

Graphite-rich pelitic schist; primarily quartz, mica, and graphite

Quartz with Mica (Schist/Pegmatite fragment)

Silicon Dioxide (SiO2) with Phyllosilicates (KAl2(AlSi3O10)(OH)2)

Red Sandstone Pebble

Arenite (Quartz Sandstone / Hematitic Sandstone)

Fossil fish slab

Fossilized fish remains, likely a laminated shale-hosted vertebrate fossil; exact taxon is indeterminate from the image

Diorite

Phaneritic intermediate plutonic rock

Chalk (Limestone)

Calcium Carbonate (CaCO3)

Tumbled white quartz

Quartz (silicon dioxide, SiO₂), likely milky quartz

Agate Sliced Nodule

Silicon Dioxide (SiO2)

Limestone

Calcium Carbonate (CaCO3)

Orthoceras Fossil in Limestone

Orthoceras regulare (Class Cephalopoda)

Limestone

Calcium Carbonate (CaCO3)

Fossil Coral (Favosites)

Favosites sp. (Phylum Cnidaria, Class Anthozoa)

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

Kaolinite-rich claystone (kaolin)

Kaolinite, Al₂Si₂O₅(OH)₄, likely in a clay-rich rock

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)

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