Sedimentary (Chemically Precipitated)

Chert (Flint)

Silicon Dioxide (SiO2)

Aragonite Star Cluster

Aragonite (Calcium Carbonate, CaCO3)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert (Nodule)

Silicon Dioxide (SiO2)

Chert

Microcrystalline quartz (SiO2)

Chert (Iron-stained or Jasperoid)

Microcrystalline Quartz (SiO2)

Iron-stained milky quartz

Quartz (SiO₂), locally limonite/goethite-stained

Chert / Flint

Microcrystalline Quartz (SiO2)

Chalcedony Agate Nodule

Silicon Dioxide (SiO2)

Red Jasper

SiO2 (Microcrystalline Quartz)

Jasper with Quartz Veining

Silicon Dioxide (SiO2) - Opaque cryptocrystalline variety of Quartz

Agate Geode

Silicon Dioxide (SiO2) - Chalcedony variety

Chert (Polished River Pebble)

Chert (SiO2)

Chert (Jaspery variety)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Common Chert)

Microcrystalline Quartz (SiO2)

Quartz (Common or Milky)

Silicon Dioxide (SiO2)

Flint (or Chert)

Silicon dioxide (Microcrystalline Quartz, $SiO_2$)

Aragonite Star Cluster

Aragonite (CaCO3)

Chert Nodule

Microcrystalline Quartz (SiO2)

Red Ochre (Hematite-rich Clay)

Limonitic/Hematitic Claystone (Fe2O3 with clay minerals)

Likely weathered sandstone or iron-stained limestone fragment

Indeterminate clastic carbonate/siliciclastic rock; likely quartz-rich sandstone or porous limestone with iron-oxide staining

Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Chert

Microcrystalline quartz (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Dyed Agate Geode

Silicon Dioxide (SiO2) - Banded Chalcedony

Banded iron formation (ironstone), likely hematite–magnetite-rich

Banded iron formation (BIF); chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and quartz (SiO₂)

Chert/Flint Nodule

Microcrystalline Quartz (SiO2)

Weathered limestone

Calcite-rich limestone (CaCO₃), possibly chalky micritic limestone

Chert (Jasper variety)

Microcrystalline Quartz (SiO2)

Native Gold (in earring form)

Gold (Au)

Banded iron formation (BIF) fragment

Metamorphosed iron formation; alternating hematite/magnetite and chert (SiO₂) layers

Banded chert pebble

Microcrystalline quartz (SiO₂), commonly called chert or flint

Iron-rich breccia or ironstone

Hematite/goethite-bearing breccia; likely Fe₂O₃–FeO(OH) with silica and iron-stained rock fragments

Chert / Flint Pebble

Microcrystalline quartz (SiO2)

Chert

Cryptocrystalline Quartz (SiO2)

Chert (and Flint)

Chert (SiO2)

Expanded Clay Pebble

Lightweight Expanded Clay Aggregate (LECA)

Orange Calcite

Calcium Carbonate (CaCO3)

Clear Quartz

Silicon dioxide (SiO2)

Blue Calcite

Calcium Carbonate (CaCO3)

Quartz Crystal (Rough)

Silicon Dioxide (SiO2)

Quartz

Silicon dioxide (SiO2)