Sedimentary (If Natural Jasper) Or Artificial (If Slag)

Breccia

Breccia - Clastic sedimentary rock

Quartz Geode

Clear Quartz (Silicon Dioxide, SiO2)

Copper-bearing Mica Schist

Mica Schist with Native Copper inclusions

Tufa

Calcareous Tufa (Calcium Carbonate, CaCO3)

Coquina / Shell Limestone

Coquina (Bioclastic Limestone)

Geode (Unopened)

Silica-lined Vug (primarily SiO2)

Sandstone

Sandstone (clastic sedimentary rock), primarily SiO2

River Stone (Basalt or Siltstone with banding)

Polished Basaltic or Siliciclastic River Cobble

Fossilized Coral (Petoskey Stone or similar)

Hexagonaria percarinata (Fossilized Rugose Coral)

Pink Halite (Himalayan Salt)

Halite (Sodium Chloride, NaCl)

Arkosic Sandstone (or Conglomeritic Sandstone fragment)

Arkose (rich in feldspar)

Coral Fossil (Petrified Coral)

Scleractinia (Order) - Calcified Fossil Skeleton (CaCO3)

Quartz Mica Schist

Mica-Quartz Schist (Chemical: SiO2 + KAl2(AlSi3O10)(OH)2)

Ironstone Concretion

Siderite or Ferruginous Concretion (FeCO3 or Iron Oxides)

Chert Pebble / Brachiopod Fossil Internal Mold

Silicon Dioxide (SiO2) / Fossil: Brachiopoda (generic internal mold)

Agate (translucent pebble)

Silicon dioxide (SiO2) - Microcrystalline Quartz

Green Calcite

Calcium Carbonate (CaCO3)

Schist

Mica Schist

Sandstone

Arenite (primarily SiO2)

Hematite

Iron(III) oxide (Fe2O3)

Red Sandstone

Arenite (Ferruginous Sandstone)

Sandstone with Bedding Planes

Arenite (Sedimentary rock composed primarily of sand-sized minerals)

Siltstone

Siltstone

Chalcedony (Common Agate)

Silicon Dioxide (SiO2)

Mica Schist

Mica Schist (predominantly Muscovite or Biotite sheet silicates)

Clear Quartz

Quartz (Silicon Dioxide, SiO2)

Agate Geode / Nodular Chalcedony

Silicon Dioxide (SiO2) with impurities

Ironstone Concretion

Siderite or Hematite Concretion

Chert (Flint)

Silicon Dioxide (SiO2)

Glauconitic Sandstone (Greenstone)

Glauconitic Siliciclastic Sandstone (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2

Ferruginous Sandstone

Arenite with Iron-Oxide Cement (FeO(OH)·nH2O / Fe2O3)

Limonite Concretion (Ironstone)

Limonite (FeO(OH)·nH2O) with Goethite and Hematite

Ferruginous Sandstone

Arenite with Iron-oxide cement (composed of Quartz and Limonite/Hematite)

Sandstone (likely Quartzose Sandstone pebble)

Arenite (primarily SiO2)

Banded Chert

Microcrystalline Quartz (SiO2)

Wishing Stone (Graywacke with Quartz Vein)

Graywacke (immature sandstone) with a SiO2 (Quartz) intrusion

Sandstone Chert Concretion

Silica-cemented Concretion (primarily SiO2)

Fossilized Coral (Petoskey Stone or similar)

Hexagonaria percarinata (Order: Rugosa)

Pyrite

Iron Sulfide (FeS2)

Banded Calcite (often commercially sold as 'Mexican Onyx' or 'Honey Onyx')

Calcite (Calcium Carbonate, CaCO3)

Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)