Sedimentary (Chemically Precipitated Mineral)

Quartz-veined Limestone

Sedimentary limestone with quartz/calcite veinlets

Banded Chert / Agate

Silicon Dioxide (SiO2)

Jasper

Microcrystalline Quartz (SiO2)

Likely milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Chalcedony Agate Nodule

Silicon Dioxide (SiO2)

Veined Limestone (Micrite) with Quartz/Calcite Veins

Calcium Carbonate (CaCO3) with Silicate or Carbonate inclusions

Tumbled limestone or calcite-rich stone

Limestone, predominantly calcite (CaCO₃); exact identification is uncertain from the photograph

Iron-stained milky quartz

Quartz (SiO₂), locally limonite/goethite-stained

Banded limestone or marble

Calcite-rich carbonate rock; likely veined limestone, possibly low-grade marble (CaCO₃)

Iron-rich concretion or weathered ironstone pebble

Goethite/limonite-bearing ironstone; commonly an iron-oxide concretion (FeO(OH)·nH₂O, variable)

Quartz pebble with a conchoidal chip

Silicon dioxide (SiO2)

Banded Iron Formation (BIF)

Banded Iron Formation (Magnetite-Hematite-Chert)

Chert

Microcrystalline Quartz (SiO2)

Banded iron formation pebble

Banded iron formation (BIF), chiefly hematite/magnetite with chert or jasper

Coquina

Biogenic Limestone (Coquina)

White Quartz Pebble

Silicon Dioxide (SiO2)

Chert (Jasper variety)

Microcrystalline Quartz (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Ferruginous Quartz on Ironstone

Silicon Dioxide (SiO2) with Hematite (Fe2O3)

Chert (Light Grey / Flint variant)

Cryptocrystalline Quartz (SiO2)

Brown chert or flint pebble

Microcrystalline quartz (SiO₂), likely chert

Chert (Quartzite-rich River Pebble)

Silicon Dioxide (SiO2)

Chert (Common Variety, Jasper)

Microcrystalline Quartz (SiO2)

Chert / Microcrystalline Quartz

Chert (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Blue apatite (likely rough/tumbled specimen)

Apatite group, commonly fluorapatite — Ca5(PO4)3F

Sandstone

Arenite (SiO2 based)

Banded Iron Formation

Banded Iron Formation (BIF)

Ironstone Nodule

Ironstone (Ferruginous Rock)

Aragonite

Aragonite (CaCO3)

Psilomelane (Black Hematite/Manganese Ore)

Barium Manganese Oxide (Formula: BaMn9O18(OH)4)

Pyrite-rich sulfide ore (likely pyrite with chalcopyrite)

Pyrite, FeS₂; possible chalcopyrite, CuFeS₂, and minor quartz or sphalerite

Jasper (specifically Bloodstone or Heliotrope variety)

Silicon Dioxide (SiO2) with iron oxide inclusions

Weathered limestone or dolostone

Calcite-rich limestone (CaCO₃), possibly dolomite-bearing

Assorted Tumbled Gemstones

Mixed oxides and silicates (including Quartz, Chalcedony, and Feldspar variants)

Aragonite Star Cluster

Aragonite (CaCO3)

Chert (Nodule)

Silicon dioxide (SiO2) - Cryptocrystalline Quartz

Chert / Flint Pebble with Fossil Cavity

Silicon Dioxide (SiO2)

Banded iron formation fragment (likely jasper-rich ironstone)

Banded iron formation (BIF), commonly hematite/goethite with chert or jasper; Fe₂O₃/FeO(OH) and SiO₂

Chert (Flint / Agate Nodule)

Silicon Dioxide (SiO2)

Green Fluorite

Fluorite (Calcium Fluoride, CaF2)

Yellow Calcite (Banded)

Calcium Carbonate (CaCO3)