Sedimentary (Chemically Precipitated Mineral)

Chert (Arrowhead or Flake)

Microcrystalline quartz (SiO2)

Septarian Nodule (Dragon Stone)

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

Honey calcite (orange calcite)

Calcite, calcium carbonate (CaCO₃)

Quartz Geode (Druzy Quartz)

Silicon Dioxide (SiO2)

Red jasper (likely iron-rich chert)

Microcrystalline quartz (SiO₂) colored by hematite/goethite; possibly ferruginous chert

Dendritic Siltstone (or Mudstone)

Siltstone with Manganese Oxide dendrites

White quartz-rich rock, likely milky quartz or quartzite

Quartz (SiO₂); possibly quartzite, a metamorphosed quartz sandstone

Iron-rich sandstone (Gozan/Ironstone)

Ferruginous Sandstone (clastic sedimentary rock)

Weathered iron-rich concretion

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

Weathered porous limestone

Calcite-rich limestone (CaCO₃), possibly fossiliferous or dolomitic

Green Chert

Silicon Dioxide (SiO2)

Chert (Jasper/Flint variety)

Silicon dioxide (SiO2)

Calcite crystal cluster

Calcite (calcium carbonate, CaCO₃)

Red Jasper (River Pebble)

Silicon Dioxide (SiO2) with iron oxide inclusions

Quartz

Silicon Dioxide (SiO2)

Tumbled yellow calcite

Calcite (CaCO₃), likely honey/yellow calcite

Tumbled honey calcite

Calcite (calcium carbonate, CaCO₃)

Honey calcite (calcareous mineral specimen)

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

Quartz Druzy in Chert Pebble

Silicon Dioxide (SiO2) - Microcrystalline & Crystalline Quartz

Banded Iron Formation (BIF) / Ironstone Conglomerate

Ironstone (Hematite/Goethite rich sedimentary rock)

Concretion (likely iron-rich sandstone or claystone concretion)

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

Calcite (likely chalky calcite fragment)

Calcite, calcium carbonate (CaCO₃)

Jasper

Microcrystalline Quartz (SiO2)

Chert

Microcrystalline silica (SiO2)

Limonite Concretion

Limonite (FeO(OH)·nH2O) Pseudomorph

Hematite

Iron(III) oxide (Fe2O3)

Weathered quartz-rich pebble

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

Polished orange calcite sphere

Calcite (CaCO₃), likely honey/orange calcite

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Oolitic Limestone (Egg Stone)

Oolite (Chemical sedimentary rock, primarily CaCO3)

Celadonite in Basalt (Green Earth)

Celadonite (K(Mg,Fe2+)(Fe3+,Al)Si4O10(OH)2)

Chert pebble

Microcrystalline silica (SiO2)

Chert (Iron-stained)

Silicon Dioxide (SiO2)

Chert (Black Chert)

Microcrystalline Silica (SiO2)

Orange calcite

Calcite (calcium carbonate, CaCO₃)

Banded Calcite (Mexican Onyx)

Calcium Carbonate (CaCO3)

Milky quartz vein fragment

Quartz (silicon dioxide, SiO₂), massive or granular variety

Tumbled chalcedony (likely milky quartz)

Microcrystalline quartz, SiO₂; possibly pale agate or quartzite

Honey calcite (yellow calcite)

Calcite, calcium carbonate (CaCO₃)

Septarian Nodule (Thunder Egg variant)

Septarian concretion (Calcite, Aragonite, and Limestone)

Quartz Pebble

Silicon Dioxide (SiO2)

Chert (Flint)

SiO2 (Microcrystalline Quartz)