Sedimentary (Physico Chemical)

Chert (specifically Jasper or Flint type)

Microcrystalline Quartz (SiO2)

Boxwork Siderite or Sepatarian Nodule Weathering

Siderite (FeCO3) with secondary mineralization or Boxwork Geode fragment

Chert / River Jasper

Microcrystalline Quartz (SiO2)

Ironstone Concretion / Goethite Nodules

Ironstone (composed primarily of Goethite FeO(OH) and Limonite)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (variations include Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint variety)

Chert (SiO2)

Chert Nodule (Commonly known as Flint or River Rock)

Silicon Dioxide (SiO2)

Chert (Flint Nodular)

Chert (Silicon dioxide, SiO2)

Chert with Quartz Veining

Silicon Dioxide (SiO2)

Green Calcite

Calcium Carbonate (CaCO3)

Milky Quartz

Silicon Dioxide (SiO2)

Chert (Nodule)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (often called Flint or Jasper based on color)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Pyritized Ammonite

Ammonitida (replaced by Iron Disulfide, FeS2)

Chert / Jasper

Microcrystalline Quartz (SiO2)

Green Chert (Jasper)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert / Flint

Chert (Cryptocrystalline Silica, SiO2)

Halite

Halite (Sodium Chloride, NaCl)

Limestone

Calcium Carbonate (CaCO3)

Limestone

Calcium Carbonate (CaCO3)

Limestone

Calcium Carbonate (CaCO3)

Calcite with iron staining

Calcium Carbonate (CaCO3)

Green Calcite

Calcium Carbonate (CaCO3)

Green Calcite

Calcium Carbonate (CaCO3)

Chert (specifically Flint or Common Opal variant)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Aragonite / Calcite Geode

Calcium Carbonate (CaCO3)

Orange Calcite

Calcite (Calcium Carbonate, CaCO3)

Limestone (Ocherous)

Calcium Carbonate (CaCO3) with Iron Oxide (Limonite)

Banded Chert (River Cobble)

Microcrystalline Quartz (SiO2)

Limestone (specifically Dolomitic Limestone)

Calcium Magnesium Carbonate (CaMg(CO3)2)

Chert (Siliceous Mudstone variant)

Microcrystalline quartz (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Chert (often called Jasper in this color)

Microcrystalline quartz (SiO2)

Chert (Smoky variety)

Microcrystalline Quartz (SiO2)

Chert (variously identified as Flint)

Microcrystalline Quartz (SiO2)

Bauxite

Bauxite (Principal ore of aluminum; mixture of minerals including Gibbsite Al(OH)3, Boehmite and Diaspore AlO(OH))

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 (often called Flint for dark varieties)

Chert (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)