Organic (Paper And Cellulose)

Calcite (Iceland Spar)

Calcite (Calcium Carbonate, CaCO3)

Slate River Stone

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

Banded Sandstone (River Cobble)

Arenite Sandstone with heavy mineral layering

Colorless faceted gemstone, likely quartz

Quartz (SiO₂), tentative identification; the photo is insufficient to confirm the material

Raw graphite-rich metamorphic rock (probable graphite schist)

Graphite schist; predominantly crystalline carbon (graphite, C) with mica and quartz

Pumice (Vesicular Rhyolite/Andesite)

Pumice (a highly vesicular volcanic glass/extrusive igneous rock)

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)

Polished green calcite (often marketed as “onyx marble” or “Pakistan onyx”)

Calcite, 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)

Banded Sandstone (Zebra Stone)

Arenite with Iron Oxide Banding (Liesegang rings)

Polished ironstone concretion with quartz/iron-oxide vein

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

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)

Tumbled orbicular granite

Granite, predominantly potassium feldspar, plagioclase, quartz, and biotite/hornblende

Polished orbicular stone, likely granite or diorite

Granite–diorite, composed mainly of feldspar, quartz, and dark amphibole/biotite

Banded Calcite (often sold as 'Travertine' or 'Mexican Onyx')

Calcium Carbonate (CaCO3)

White Marble

Recrystallized Calcite (CaCO3)

Polished black stone sphere (likely black basalt or black tourmaline)

Most likely fine-grained basalt (plagioclase–pyroxene); mineral identification is uncertain from the image alone

Tumbled orange chalcedony or jasper pebble

Microcrystalline quartz, SiO₂; possibly iron-stained chalcedony/jasper

Polished brown river pebble

Likely quartzite or weathered metabasalt; exact identification requires hardness and streak tests

Rounded reddish-brown river cobble, likely weathered granite or granitic gneiss

Feldspar–quartz–mica rock; exact identification requires a fresh surface or testing

Petoskey Stone

Hexagonaria percarinata (Fossilized Rugose Coral)

Polished malachite–agate breccia (likely)

Microcrystalline quartz/chalcedony (SiO₂) with iron-oxide staining; exact identification requires testing

Polished banded jasper

Microcrystalline quartz (SiO₂), commonly with iron-oxide and clay-mineral bands

Rounded river pebble

Probably quartz-rich sandstone or lithic sandstone; exact identification requires testing

Dark river pebble, likely basalt or fine-grained volcanic rock

Basalt (probable); mostly plagioclase and pyroxene, with possible magnetite

Tumbled banded quartzite or jasper

Silica-rich quartzite; likely iron-oxide-stained quartz (SiO₂)

Tumbled fossiliferous limestone

Bioclastic limestone, likely crinoidal or shell-rich limestone (calcite, CaCO₃)

Bauxite

Bauxite (Al(OH)3 mixed with Fe2O3 and clay minerals)

Quartz-veined Limestone

Sedimentary limestone with hydrothermal quartz/calcite veins (CaCO3 / SiO2)

Rounded gray river pebble, likely basalt or andesite

Fine-grained mafic volcanic rock; commonly basalt (plagioclase, pyroxene, and possible olivine)

Likely graphite-rich ore or galena-bearing rock

Graphite (C) or galena (PbS), identification uncertain from photograph