Sedimentary (Chemically Precipitated)

Quartz-veined Sandstone

Sedimentary rock with quartz vein (SiO2)

Tumbled honey calcite

Calcite (calcium carbonate, CaCO₃)

Quartz and Mixed Sedimentary Rocks

Silicon Dioxide (SiO2) mixed with various clastic sedimentary lithologies

Jasper

Silicon dioxide (Microcrystalline quartz, SiO2 with iron oxide impurities)

Quartz Geode

Silicon Dioxide (SiO2) in Geode form

Honey calcite (calcareous mineral specimen)

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

Ferruginous Sandstone

Arenite with Iron-Oxide Cement (SiO2 with Fe2O3/FeO(OH))

Banded iron formation (iron-rich jasper/chert)

Banded iron formation, composed mainly of hematite–magnetite with microcrystalline quartz (jasper/chert)

Dark flint or chert fragment

Microcrystalline quartz (SiO₂), likely chert/flint

Banded Calcite (Mexican Onyx)

Calcium Carbonate (CaCO3)

Honey calcite (yellow calcite)

Calcite, calcium carbonate (CaCO₃)

Calcite

Calcite (CaCO₃), likely crystalline limestone or marble fragment

Calcite (likely chalky calcite fragment)

Calcite, calcium carbonate (CaCO₃)

Hematite

Iron(III) oxide (Fe2O3)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Yellow Ochre / Limonite

Limonite (FeO(OH)·nH2O)

Iron-rich chert or jasper

Microcrystalline quartz (SiO₂), variably stained by iron oxides/hydroxides

Septarian Nodule (Dragon Stone)

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

Ferruginous Breccia

Breccia with Iron-rich (Hematite/Goethite) Matrix

Banded Chert

Chert (Silicon Dioxide, SiO2)

Likely chert/flint fragment

Microcrystalline quartz (SiO₂), possibly partially weathered chert

Veined Limestone (Micrite) with Quartz/Calcite Veins

Calcium Carbonate (CaCO3) with Silicate or Carbonate inclusions

Chert Nodules in Limestone

Microcrystalline Quartz (SiO2) within Calcium Carbonate (CaCO3)

Ferruginous Sandstone (Gozzanous)

SiO2 (Quartz) with FeO(OH) (Goethite) or Fe2O3 (Hematite) coating

Red Sandstone

Quartzose Sandstone (primarily quartz grains cemented by iron oxides)

Weathered limestone

Limestone, predominantly calcite (CaCO₃)

Wishing Stone / Banded Quartz Vein Pebble

Sedimentary pebble with hydrothermal quartz veins (SiO2)

Banded iron formation (ironstone)

BIF; chiefly hematite/magnetite with chert or jasper (Fe₂O₃/Fe₃O₄ and SiO₂)

Yellow calcite

Calcite (CaCO₃), likely honey or amber calcite

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

Polished orange calcite sphere

Calcite (CaCO₃), likely honey/orange calcite

Raw honey calcite

Calcite (calcium carbonate, CaCO₃)

Flint Nodule with Chalk Cortex

Chert (Microcrystalline Quartz) SiO2

Fossiliferous Limestone

Biogenic Limestone (CaCO3)

Banded iron formation (iron-rich metamorphic rock)

Banded iron formation (BIF), chiefly hematite/magnetite with chert or quartz (Fe₂O₃/Fe₃O₄ and SiO₂)

Chert / Flint

Microcrystalline Quartz (SiO2)

Banded Chert / Flint

Silicon dioxide (SiO2)

Concretion (likely iron-rich sandstone or claystone concretion)

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

Jasper with Quartz Veining

Microcrystalline quartz (SiO2) with iron oxide impurities

Selenite (gypsum)

Gypsum, CaSO₄·2H₂O; fibrous variety often called satin spar

Weathered iron-rich mineral concretion

Likely limonite/goethite concretion (hydrated iron oxides), possibly a weathered ironstone fragment