Sedimentary (Secondary Formation)

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Chert (Iron-stained)

Chert (Microcrystalline and Cryptocrystalline Quartz, SiO2)

Banded Chert (or Flint)

Microcrystalline Quartz (SiO2)

Chert (Arrowhead variety)

Chert (SiO2)

Chert (Jasper variety)

Chert (SiO2)

Chert (Jasper/Flint variety)

Silicon dioxide (SiO2)

Chert (Jasper/Agate variety)

Microcrystalline Quartz (SiO2)

Chert (Iron-stained)

Chert (Microcrystalline Quartz, SiO2)

Red Jasper (Chert)

Silicon Dioxide (SiO2) with iron oxide inclusions

Anthracite Coal

Coal (predominantly carbon)

Gneiss (Granitic Gneiss)

Gneiss (composed primarily of Quartz, Feldspar, and Mica/Amphibole)

Red Quartzite

Quartzite (SiO2)

Jasper

Jasper (Silicon Dioxide, SiO2)

Chert / Flint

Microcrystalline or cryptocrystalline quartz (SiO2)

Pink Banded Onyx (Mexican Onyx / Calcite)

Calcite (CaCO3) - microcrystalline calcium carbonate

Chert (Black Chert / Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Clear Quartz (or Rock Crystal)

Quartz (SiO₂)

Arkosic Sandstone

Arkose (Clastic Sedimentary Rock)

Stromatolite

Laminated biogenic sedimentary structure (formed by Cyanobacteria)

Red Jasper or Chert

Jasper (SiO2, a variety of chalcedony with iron oxide impurities), Chert (SiO2)

Chert (Jasper/Agate variety)

Microcrystalline Quartz (SiO2)

Chert Pebble (Jasper/Quartz variety)

Microcrystalline Quartz (SiO2)

Ironstone Concretion (Siderite Nodules)

Siderite (FeCO3) in Mudstone or Sandstone matrix

Belemnite Fossil

Belemnitida (extinct order of Cephalopods)

Chert (Yellow Jasper variant)

Microcrystalline Quartz (SiO2)

Chert (Tan/Grey variety)

Silicon Dioxide (SiO2)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Geode with Quartz Crystal Cavity

Silicon Dioxide (SiO2) in Calcareous/Siliceous Matrix

Oolite or Oolitic Limestone

Oolitic Limestone (Principal mineral: Calcite, CaCO3)

Oolitic Limestone / Fossiliferous Chert

Oolitic Limestone (CaCO3) / Silicified Limestone

Honeycomb Calcite

Calcite (Calcium Carbonate, CaCO3)

Conglomerate

Conglomerate (clastic sedimentary rock)

Black Kyanite

Kyanite (Al2SiO5) with carbonaceous inclusions

Red Sandstone

Clastic Terrigenous Sedimentary Rock (typically Hematitic Quartz Arenite or Arkose)

Red Sandstone

Clastic Sedimentary Mineraloid (predominantly Quartz grains with Iron Oxide cement)

Quartz

Quartz (SiO₂)

Jasper (likely Lake Superior Jasper)

Jasper (Silicon Dioxide, SiO2)

Jasper (Iron Oxide Rich)

Silicon Dioxide (SiO2) with Fe2O3 (Hematite/Goethite) inclusions

Chert (Flint nodule)

Silicon dioxide (SiO2)

Chert Nodule

Microcrystalline Silica (SiO2)

Quartz

Quartz (Silicon Dioxide - SiO2)

Oolitic Chert

Silicon Dioxide (SiO2) with oolitic texture