Sedimentary (Chemically Precipitated)

Brown chert or flint pebble

Microcrystalline quartz (SiO₂), likely chert

Celestite Geode

Strontium Sulfate (SrSO4)

Pyrite

Iron Sulfide (FeS2)

Jasper

Microcrystalline Quartz (SiO2)

Jasper in Quartz / Brecciated Jasper

Silicon Dioxide (SiO2) with iron oxide impurities

Jasper

Microcrystalline quartz (SiO2)

Jasper

Microcrystalline quartz (SiO2)

Likely calcite fragment

Calcite (calcium carbonate, CaCO₃)

Calcite crystal fragment

Calcite (calcium carbonate, CaCO₃)

Limonite (Ironstone)

Limonite (FeO(OH)·nH2O)

Weathered limestone or dolostone

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

Honey calcite crystal

Calcite (calcium carbonate, CaCO₃)

Chert (Nodule)

Silicon dioxide (SiO2) - Cryptocrystalline Quartz

Orange Calcite

Calcium Carbonate (CaCO3)

River Chalcedony / Agate

Chalcedony (Silicon Dioxide, SiO2)

Carnelian Agate

Carnelian (Silicon Dioxide - SiO2)

Banded iron formation (iron-rich jasper/chert)

Banded iron formation, chiefly quartz (SiO₂) with hematite, magnetite, and/or goethite (Fe oxides/hydroxides)

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

River Pebble (Greywacke or Chert mix)

Silicon Dioxide (SiO2) with varying mineral impurities

Chert Pebble with Quartz Veining

Microcrystalline Quartz (SiO2)

Pyrite

Iron Sulfide (FeS2)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Ferruginous Quartz on Ironstone

Silicon Dioxide (SiO2) with Hematite (Fe2O3)

Dead Sea Salt Crust

Halite (NaCl)

Chert with Manganese Dendrites / River Silt Overlays

Cryptocrystalline Quartz (SiO2) with Manganese Oxides

Sandstone

Arenite (Sedimentary Rock)

Chert or flint nodule

Microcrystalline quartz (SiO₂), likely chalcedony-rich chert

Banded iron formation (ironstone)

Banded iron formation, chiefly hematite/magnetite with chert (SiO₂)

Banded Iron Formation (BIF)

Banded Iron Formation with Hematite and Jasper

Jasper

Microcrystalline quartz (SiO2)

Liesegang Banded Sandstone (Concretion / Weathered Pebble)

Sandstone showing Liesegang rings / Weathering rind (SiO2 with iron oxides)

Peach/orange calcite cluster

Calcite (CaCO₃), likely botryoidal or scalenohedral aggregate

Soil Clod / Caliche Nodules

Pedogenic Calcrete / Clay aggregate

Banded Chert

Microcrystalline Quartz (SiO2)

Honey calcite on matrix

Calcite, CaCO₃

Ferruginous Sandstone

Arenite with iron oxide cement (predominantly SiO2 with Fe2O3)

Quartz in Matrix

Silicon Dioxide (SiO2) in host rock matrix

Quartz

Silicon Dioxide (SiO2)

Red Jasper Pebble

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Quartz (Milky / Massive Quartz)

Silicon Dioxide (SiO2)