Limestone

Chert (Smooth River Pebble)

Silicon Dioxide (SiO2)

Chert (Jasper/Common Opal transition)

Microcrystalline Quartz (SiO2) with iron oxide inclusions

Quartz Geode

Silicon Dioxide (SiO2)

Oolitic Chert

Silicon Dioxide (SiO2) with oolitic texture

Petoskey Stone

Hexagonaria percarinata (Fossilized Rugose Coral)

Chert (v. Flint)

Sedimentary Cryptocrystalline Quartz (SiO2)

Chert (Arrowhead)

Chert (primarily Microcrystalline Silica, SiO2)

Chert (Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Chert Nodule)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Green Fluorite

Fluorite (Calcium Fluoride, CaF2)

Chert (Flint)

Chert (Cryptocrystalline variety of Quartz, SiO2)

Chert (specifically Yellow or River Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Porphyritic Basalt (Flower Stone)

Basalt with Feldspar phenocrysts

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Banded Calcite (often sold as 'Ocean Jasper' or 'Caribbean Calcite' variant)

Calcium Carbonate (CaCO3) with potential Aragonite inclusions

Chert (specifically Flint or Dark Chalcedony)

Silicon Dioxide (SiO2)

Chert (with Quartz vein)

Chert (Silicon Dioxide, SiO2)

Granite

Granite (composed primarily of Quartz SiO2, Alkali Feldspar KAlSi3O8, and Plagioclase Feldspar)

Chert Pebble with Quartz Veining

Microcrystalline Quartz (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Chert (specifically Gray/Blue Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartzite

Quartzite (mostly SiO2)

Chert Nodule (Commonly known as a Flint or River Cobble)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Marble

Recrystallized Calcite (CaCO3)

Chert Pebble/Nodule

Chert (a microcrystalline or cryptocrystalline sedimentary form of quartz, SiO2)

Chert / Flint

Cryptocrystalline Quartz (SiO2)

White Marble

Recrystallized Calcite (CaCO3)

Quartz Geode in Sedimentary Matrix

Silicon Dioxide (SiO2) within a limestone/dolostone host

Chert / Flint

Microcrystalline or cryptocrystalline quartz (SiO2)

Chert (Flint)

Chert (Cryptocrystalline Quartz, SiO2)

Chert (specifically a Chert Nodule or Flint)

Cryptocrystalline Quartz (SiO2)

Chert / Jasper

Microcrystalline Quartz (SiO2)

Chert (Blue-Gray Chert)

Microcrystalline quartz (SiO2)

Black Limestone with Calcite Veining

Bituminous Limestone (CaCO3 with Organic Carbon inclusions)

Limestone with Weathering Rind

Calcium Carbonate (CaCO3) - Bioclastic or Micritic Limestone

White Marble (Industrial/Architectural)

Recrystallized Calcite (CaCO3)

Chert (Flint variety)

Silicon Dioxide (SiO2)

Chert (often called Flint)

Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)

Chert (specifically Flint or Jasper variant)

Microcrystalline quartz (SiO2)

Chert (Honey Chert / Flint)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Chert (Flint)

Cryptocrystalline Quartz (SiO2)