Sedimentary (Fossilized Organic Matter)

Chert / Quartz Pebble

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (variously known as Flint or Jasper)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Anthracite Coal

Anthracite (Carbon-based metamorphic rock)

Chert (Grey/Black variety)

Chert (Silicon Dioxide, SiO2)

Chert (often called Flint in this context)

Silicon Dioxide (SiO2)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Tan/Brown variety)

Chert (Microcrystalline Quartz, SiO2)

Chert (Cherty Limestone or Flint)

Microcrystalline Silica (SiO2)

Chert (Nodule)

Silicon Dioxide (SiO2)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Iron-stained)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (often called Flint or Jasper based on color)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Nodular or Massive Variety)

Cryptocrystalline Quartz (SiO2)

Chert with Quartz/Calcite Vein

Microcrystalline Silica (SiO2)

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide)

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (specifically Flint or Jasper variant)

Microcrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Chert (variations include Flint/Jasper)

Cryptocrystalline Silicon Dioxide (SiO2)

Chert (Iron-stained)

Chert (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline quartz (SiO2)

Chert Pebble

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (primarily Quartz/Chalcedony, formula SiO2)

Chert (Black Chert/Flint)

Cryptocrystalline Quartz (SiO2)

Chert (varietal Flint or Jasper)

Microcrystalline Quartz (SiO2)

Chert (varieties include Flint and Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (containing Fossil Inclusions)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (SiO2 permineralization)

Petrified Wood

Silicified Wood (primarily SiO2)

Chert (with Iron Staining)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Chert (and Limestone)

Silicon Dioxide (SiO2)

Chert (White-Tan variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert / Flint

Microcrystalline Quartz (SiO2)

Chert (Jasper/Iron-stained Quartzite)

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Chert (Nodule/Pebble)

Chert (Silicon Dioxide, SiO2)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Moss Agate

Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxides