Organic (Mineraloid)

Chert (Green variety)

Silicon Dioxide (SiO2)

Chert (specifically Green Chert/Jasper)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Fossilized Oyster Shell (Limestone/Coquina)

Crassostrea (Fossilized Bivalve), Calcium Carbonate (CaCO3)

Chert with Limestone matrix

Microcrystalline silica (SiO2) in Calcite (CaCO3) matrix

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (White Chert or Flint)

Microcrystalline Quartz (SiO2)

Chert (and Limestone)

Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert with Iron Oxide Staining

Microcrystalline Quartz (SiO2) with Limonite/Goethite staining

Chert (Jasper)

Silicon Dioxide (SiO2)

Quartz Geode

Crystalline Silicon Dioxide (SiO2) in sedimentary/volcanic host

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Nodule)

Silicon Dioxide (SiO2)

Chert (and Flint nodule)

Silicon Dioxide (SiO2)

Petrified Wood

Silicified wood (Quartz/Chalcedony replacement of cellulose)

Chert (Green variety)

Silicon Dioxide (SiO2)

Chert (Flint variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (Siliceous Mudstone variant)

Microcrystalline quartz (SiO2)

Fossilized Crab Carapace (Concretion)

Decapoda (fossil), typically preserved in calcite or siderite concretion

Chert Arrowhead (Projectile Point)

Microcrystalline Quartz (SiO2)

Chert (often called Jasper in this color)

Microcrystalline quartz (SiO2)

Jasper

Silicon dioxide (SiO2)

Glauconitic Sandstone (Greensand)

Glauconitic quartz wacke or arenite

Chert (Smoky variety)

Microcrystalline Quartz (SiO2)

Chert (variously identified as Flint)

Microcrystalline Quartz (SiO2)

Chert (Field Flint)

Microcrystalline Quartz (SiO2)

Gray Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Chert (often called Flint or Jasper when red)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (Nodule)

Silicon Dioxide (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Moqui Marbles

Iron Oxide Concretion (Hematite/Goethite)

Chert (Flint)

Chert (SiO2)

Chert (Chert Nodule in Limestone)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chalcedony (Agatized Coral / Rough Chalcedony Node)

Silicon Dioxide (SiO2)

Chert (Flint variety)

Microcrystalline Quartz (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2) with iron oxide impurities

Chert (often called Flint)

Microcrystalline Quartz (SiO2)