Mineral Or Sedimentary (If Chert)

Weathered flint or chert fragment

Microcrystalline quartz (SiO₂), likely chert/flint

Rough amber-like brown mineral specimen

Uncertain from photograph; possibly iron-stained quartz, common opal, or resinous amber

Mookaite Jasper

Radiolarite (Silicified radiolarian chert)

Brecciated Jasper

Silicon Dioxide (SiO2) with Hematite and Epidote/Chlorite inclusions

Chert (Cream Variety)

Microcrystalline silica (SiO2)

Banded Chert (Flint)

Silicon Dioxide (SiO2)

Chert (variations include Flint/Jasper)

Cryptocrystalline Quartz (SiO2)

Chert (Flint Pebbles)

Microcrystalline Quartz (SiO2)

Rounded gray-green chert (likely silicified limestone)

Microcrystalline quartz/chalcedony (SiO₂), possibly jasper or siliceous limestone

Chert (Jasper/Flint variant)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Limonite-stained Chert

Microcrystalline Quartz (SiO2) with Goethite/Limonite (FeO(OH)·nH2O)

Chert (Jasper/Flint variant)

Silicon Dioxide (SiO2)

Chert (often called Flint)

Cryptocrystalline Quartz (SiO2)

Chert with Iron Oxide Staining

Microcrystalline Quartz (SiO2) with Limonite/Goethite staining

Tumbled jasper or chert

Microcrystalline quartz (SiO₂), likely jasper/chalcedony

Weathered iron-rich sandstone or ferruginous chert

Likely quartz-rich sandstone (SiO₂) cemented or stained by iron oxides such as goethite/hematite

Likely weathered iron-rich concretion or jasper

Goethite/hematite-bearing chert or ferruginous concretion (identification uncertain from photograph)

Chert / River Pebble

Silicon Dioxide (SiO2)

Chert (Nodule)

Silicon Dioxide (SiO2)

Chert (flint) with a pale quartz vein

Microcrystalline quartz, SiO₂; the white vein is likely quartz or chalcedony

Red jasper (likely tumbled or naturally worn)

Jasper, microcrystalline quartz/chalcedony (SiO₂), colored mainly by iron oxides

Banded Iron Formation (BIF) / Chert

Banded Iron Formation (SiO2 with Fe2O3 / Fe3O4)

Polished jasper pebble

Jasper, microcrystalline quartz (SiO₂) with iron-oxide and clay inclusions

Chert / Jasper

Silicon Dioxide (SiO2)

Chert or chalcedony fragment

Microcrystalline quartz (SiO₂), likely translucent chert/chalcedony

Banded Chert

Silicon Dioxide (SiO2)

Tumbled dark stone, possibly basalt or iron-rich chert

Indeterminate; likely fine-grained basalt (plagioclase–pyroxene) or ferruginous chert

Chert (with Iron Staining)

Silicon Dioxide (SiO2)

Tan chert or fine-grained sandstone fragment

Microcrystalline quartz (SiO₂), possibly chalcedony-rich chert

Chert or silicified sedimentary fragment (tentative)

Microcrystalline quartz (SiO₂), possibly silicified limestone or fossil-bearing chert

Chert or chalcedony fragment

Microcrystalline quartz (SiO₂), likely ferruginous chalcedony/jasper

Polished flint/chert pebble

Microcrystalline quartz (SiO₂), commonly called chert or flint

Chert (possibly a worked stone flake)

Microcrystalline quartz, SiO₂

Chert (Flint)

Chert (Cryptocrystalline Silicon Dioxide, SiO2)

Chert with Calcite Veining

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

Quartz (Chert/Chalcedony variety)

Silicon Dioxide (SiO2)

Chert (often referred to as Flint)

Chert (Microcrystalline Quartz, SiO2)

Chalcedony Nodule (Commonly known as Agate or Chert)

Microcrystalline Quartz (SiO2)

Likely white quartz or quartz-rich pebble

Quartz (silicon dioxide, SiO₂), possibly a small polished/tumbled specimen

Chert (specifically Gray/Blue-Gray Chert)

Chert (SiO2)

Chert Pebble with Inclusion

Microcrystalline Quartz (SiO2)

Flint/chert fragment (likely weathered chert nodule)

Microcrystalline quartz (SiO₂), commonly chalcedony with possible calcite or iron-oxide staining