Marble

Chert (variously known as Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint variety)

Chert (SiO2)

Amber (Dark/Black Variety)

Succinite (Resinite), C10H16O

Sandstone

Arenite (Sedimentary rock composed of sand-sized minerals or rock grains)

Basalt Pebble

Basalt

Red Siltstone

Siltstone (primarily quartz and feldspar sized 0.0039 to 0.0625 mm)

Chert (Jasper/Flint variety)

Silicon Dioxide (SiO2)

Sandstone (with Iron Staining)

Clastic Sedimentary Rock (primarily SiO2)

Fossil Shell Fragment (possibly Brachiopod or Bivalve)

Calcium Carbonate (CaCO3) - Phylum Brachiopoda or Mollusca

Chert (Jasper variety)

Silicon dioxide (SiO2) - Microcrystalline Quartz

Green Chert (Jasper)

Silicon Dioxide (SiO2)

Diamond (or Cubic Zirconia simulant)

Carbon (C) - Diamond / Zirconium dioxide (ZrO2) - CZ

Chert (often called Flint for dark variants)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone (Ferruginous)

Arenite (Fe-rich)

Ferruginous Sandstone

Sandstone (arenite) with Limonite/Goethite cement

Limestone

Calcium Carbonate (CaCO3)

Serpentinite

Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4

Diamond (in Jewelry)

Carbon (C)

Limestone

Calcium Carbonate (CaCO3)

Chert (variously known as Flint or River Pebble)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Serpentine

Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)3(Si, Al, Fe)2O5(OH)4

Hag Stone (Banded Chert or Limestone with Borehole)

Microcrystalline Quartz (Chert) or Calciferous Siltstone (CaCO3/SiO2)

Brachiopod Fossil

Phylum Brachiopoda (likely Order Rhynchonellida or Spiriferida)

Gastropod Steinkern (Fossilized Snail Cast)

Phylum Mollusca, Class Gastropoda (Commonly CaCO3 or SiO2 after replacement)

Quartz (Milky Quartz Pebble)

Silicon Dioxide (SiO2)

Chert (Lightly weathered variety)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Horn Coral Fossil

Rugosa (extinct order of solitary corals)

Yellow Jasper

Silicon Dioxide (SiO2) with iron inclusions

Oolitic Chert

Silicon Dioxide (SiO2) with Oolitic texture

Limestone

Calcium Carbonate (CaCO3)

Green Calcite

Calcium Carbonate (CaCO3)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Diamond

Carbon (C)

Serpentinite

Serpentinite (composed primarily of Serpentine minerals: Mg3Si2O5(OH)4)

Chert (often called Flint or Agate nodule)

Cryptocrystalline Quartz (SiO2)

Banded Chert with Quartz Veining

Microcrystalline Quartz (SiO2)

Chert (Nodule)

Silicon Dioxide (SiO2)

Sandstone

Arenite (primarily Quartz, SiO2)

Limestone

Limestone (Calcium Carbonate - CaCO3)

Chert

Microcrystalline Quartz (SiO2)

Chert (variant Flint/Jasper)

Microcrystalline Opaline Silica (SiO2)

Chert (Beach Pebble)

Silicon Dioxide (SiO2)