Sedimentary (Chemically Precipitated)

Chert with Calcite Veining

Microcrystalline Quartz (SiO2) with Calcium Carbonate (CaCO3) veins

Chert (Quartz Variety)

Chert (mostly SiO2 / Silicon Dioxide)

Weathered quartz-rich pebble

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

White Quartz Pebble

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

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

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

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

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert (varieties including Flint or Jasper)

Microcrystalline Quartz (SiO2)

Chert (specifically Cryptocrystalline Quartz)

Silicon dioxide (SiO2)

Wood Stone (Dragon Stone variant)

Argillaceous Sedimentary Rock

Chert / River Pebble

Silicon Dioxide (SiO2)

Ironstone concretion (probable hematite–goethite-rich ironstone)

Iron oxide/hydroxide concretion; chiefly hematite (Fe₂O₃) and goethite (FeO(OH)), with possible magnetite and quartz

Red Jasper

Microcrystalline Quartz (SiO2)

Iron Ore (Hematite/Magnetite mixture)

Ferrous Oxide (Fe2O3 / Fe3O4)

Limonite/goethite-rich ironstone concretion (probable)

Goethite–limonite, chiefly FeO(OH)·nH₂O, possibly with hematite and manganese oxides

Milky Quartz

Silicon Dioxide (SiO2)

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

Tumbled chalcedony / quartz pebble

Microcrystalline quartz (SiO₂), likely chalcedony with iron-oxide staining

Ironstone concretion (likely limonite/goethite-rich)

Iron-oxide-cemented sediment, commonly goethite (FeO(OH)) and/or limonite

Orange Calcite

Calcite (Calcium Carbonate, CaCO3)

Metallic sulfide ore, possibly pyrite-rich

Pyrite (FeS₂), potentially mixed with chalcopyrite, galena, or iron oxides

Flint

SiO2 (Microcrystalline Quartz / Chert)

Chert (Flint)

Silicon Dioxide (SiO2)

Chert (containing Quartz)

Microcrystalline Silica (SiO2)

Aragonite Star Cluster

Aragonite (CaCO3)

Quartz (Milky/Bull Quartz)

Silicon Dioxide (SiO2)

Chert (Jasper-like Silicate)

Silicon Dioxide (SiO2)

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Flint/Chert Nodule in Limestone

Sedimentary rock containing microcrystalline quartz (SiO2) within a calcium carbonate (CaCO3) matrix

Chert (Jasper variation)

Silicon Dioxide (SiO2)

Assorted Tumbled Gemstones

Mixed oxides and silicates (including Quartz, Chalcedony, and Feldspar variants)

Chert (Jasper/Agate mix)

Microcrystalline Quartz (SiO2)

Chert (Agatized)

Silicon dioxide (SiO2)

Chert (Iron-stained)

Chert (Silicon Dioxide, SiO2)

Likely milky quartz pebble

Quartz (silicon dioxide, SiO₂)