Sedimentary (Chemically Precipitated)

Quartz Pebble

Silicon Dioxide (SiO2)

Wood Stone (Dragon Stone variant)

Argillaceous Sedimentary Rock

Chert (Quartz Variety)

Chert (mostly SiO2 / Silicon Dioxide)

Banded Chert

Silicon Dioxide (SiO2)

Quartz pebble

Silicon dioxide (SiO2)

Dyed Agate

Silicon Dioxide (SiO2) with artificial pigment

Dyed Blue Agate

Silicon dioxide (SiO2) with artificial pigment

Sandstone (Ferruginous)

Arenite (composed primarily of SiO2 with Fe2O3 cement)

Blue Celestite

Strontium Sulfate (SrSO4)

Chalcedony

Silicon Dioxide (SiO2)

Milky Quartz (Tumbled Chalcedony)

Silicon Dioxide (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert (varieties including Flint or Jasper)

Microcrystalline Quartz (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Opal

Hydrated amorphous silica (SiO2·nH2O)

Sulfur-bearing Limestone (Solfatara Specimen)

Sulfur-rich Bio-limestone (Calcium Carbonate with Native Sulfur, S8)

Tumbled limestone or calcite-rich stone

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

Ferruginous Sandstone

Arenite with Hematite/Goethite cement

Moqui Marble (Ironstone Concretion)

Goethite/Hematite Concretion (Fe2O3 / FeO(OH))

Ferruginous Sandstone

Arenite with Iron-oxide cement (composed of Quartz and Limonite/Hematite)

Weathered iron-rich concretion (probable limonite/goethite)

Limonite–goethite aggregate, approximately FeO(OH)·nH₂O

Quartz

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (iron-rich)

Chert (specifically Cryptocrystalline Quartz)

Silicon dioxide (SiO2)

Weathered quartz-rich pebble

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

Limestone

Calcium Carbonate (CaCO3)

Calcite-rich limestone fragment

Limestone, predominantly calcite (CaCO₃), possibly micritic or fossiliferous

Ferruginous Sandstone (Gritstone)

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

Septarian Nodule Segment (Commonly known as Dragon Stone or Lightning Stone)

Septarian Nodule (CaCO3 / Hydrated Calcium Carbonate)

Dendritic Siltstone (or Mudstone)

Siltstone with Manganese Oxide dendrites

Septarian Nodule (Thunder Egg variant)

Septarian concretion (Calcite, Aragonite, and Limestone)

Chert / River Pebble

Silicon Dioxide (SiO2)

Flint

SiO2 (Microcrystalline Quartz / Chert)

Weathered iron-rich concretion or ironstone nodule

Goethite–hematite limonite concretion (FeO(OH), Fe₂O₃, and hydrous iron oxides)

Flint/chert projectile point

Microcrystalline quartz (SiO₂), archaeologically worked into a bifacial point

Calcite (honey calcite)

Calcite, calcium carbonate (CaCO₃)

Tumbled dark stone, likely banded iron formation or hematite-rich jasper

Hematite-bearing quartz/jasper; probable iron oxide–silica aggregate

Likely tumbled white quartz or quartzite pebble

Quartz (SiO₂), possibly quartzite

Raw graphite-rich metamorphic rock (probable graphite schist)

Graphite schist; predominantly crystalline carbon (graphite, C) with mica and quartz

Dyed Howlite (often sold as Turquenite)

Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)

Limonite Concretion

Limonite (FeO(OH)·nH2O) Pseudomorph

Chert (Flint)

Silicon Dioxide (SiO2)