Sedimentary (Chemically Precipitated Mineral)

Tumbled honey calcite

Calcite (calcium carbonate, CaCO₃)

Iron-rich concretion or weathered ironstone

Goethite–hematite-rich limonite (FeO(OH)·nH₂O / Fe₂O₃)

Tumbled green fluorite

Fluorite (calcium fluoride, CaF₂)

Chert pebble

Microcrystalline silica (SiO2)

Tumbled yellow calcite

Calcite (CaCO₃), likely honey/yellow calcite

Honey calcite (calcareous mineral specimen)

Calcite, CaCO₃; likely honey/yellow calcite with minor iron-oxide staining

Chert

Microcrystalline silica (SiO2)

Chert (Iron-stained)

Silicon Dioxide (SiO2)

Chert (Black Chert)

Microcrystalline Silica (SiO2)

Septarian Nodule (Dragon Stone)

Septarian Concretion (CaCO3 + CaMg(CO3)2 + SiO2)

White quartz geode nodule

Quartz (SiO₂), likely a quartz-lined geode or vug in a host rock

Iron-rich sandstone (Gozan/Ironstone)

Ferruginous Sandstone (clastic sedimentary rock)

Weathered quartz-rich pebble

Likely milky quartz (SiO₂), possibly a quartz-rich vein fragment

Small ironstone pebble (likely limonite/goethite-rich concretion)

Goethite, α-FeO(OH), with possible limonite and quartz or clay impurities

Jasper

Microcrystalline quartz (SiO2)

Banded Calcite (Mexican Onyx)

Calcium Carbonate (CaCO3)

Soil Clod / Caliche Nodules

Pedogenic Calcrete / Clay aggregate

Chrysocolla in Matrix

Hydrated copper phyllosilicate, (Cu,Al)2H2Si2O5(OH)4·nH2O

Dendritic Siltstone (or Mudstone)

Siltstone with Manganese Oxide dendrites

Chert (with Manganese Dendrites)

Chert (Cryptocrystalline Quartz, SiO2)

Chert (and Flint)

Silicon Dioxide (SiO2)

Polished orange calcite sphere

Calcite (CaCO₃), likely honey/orange calcite

Quartz Geode (Druzy Quartz)

Silicon Dioxide (SiO2)

Ferruginous Sandstone

Arenite with iron oxide cement (predominantly SiO2 with Fe2O3)

Banded agate (likely polished/tumbled)

Agate, a banded variety of chalcedony (microcrystalline quartz, SiO₂)

Limestone

Calcium carbonate (CaCO3) / Limestone

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Bandized Calcite

Calcium Carbonate (CaCO3)

Chert (Flint Flake)

Microcrystalline Quartz (SiO2)

Weathered iron-rich concretion

Goethite–hematite limonite concretion, likely with quartz and clay minerals

Likely tumbled white quartz or quartzite pebble

Quartz (SiO₂), possibly quartzite

Orange calcite

Calcite (calcium carbonate, CaCO₃)

Honey calcite (yellow calcite)

Calcite, calcium carbonate (CaCO₃)

Chert (River Pebble)

Chert (Cryptocrystalline Quartz, SiO2)

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

Calcite (Calcium Carbonate, CaCO3)

Jasper

Microcrystalline Quartz (SiO2)

Quartz Geode

Silicon Dioxide (SiO2) in Geode form

Hematite

Iron(III) oxide (Fe2O3)

Concretion (likely iron-rich sandstone or claystone concretion)

Diagenetic carbonate/iron-oxide concretion; exact mineralogy requires testing

Blue-green calcite

Calcite (CaCO₃), likely copper-bearing or otherwise inclusions-colored

Banded Iron Formation (BIF) / Ironstone Conglomerate

Ironstone (Hematite/Goethite rich sedimentary rock)

Calcite (likely chalky calcite fragment)

Calcite, calcium carbonate (CaCO₃)