Industrial Byproduct (Anthropogenic Material)

Sunstone

Oligoclase (Plagioclase Feldspar Group) - (Ca, Na)(Al, Si)4O8

Amethyst

SiO2 (Silicon Dioxide) - Purple variety of Quartz

Sandstone

Arenite (Siliclastic sedimentary rock)

Coquina / Fossiliferous Limestone

Coquina (composed primarily of Calcium Carbonate / CaCO3)

Red Sandstone (Iron-rich Sandstone)

Clastic Sedimentary Rock - Quartz Arenite / Arkose with Hematite Cement

Sandstone (with Iron Staining)

Clastic Sedimentary Rock (primarily Quartz, SiO2)

Sandstone

Arenite (primarily SiO2)

Quartzite with Hematite

Metamorphosed Quartz Sandstone (SiO2 with Fe2O3 inclusions)

Banded Gneiss (River Cobble)

Gneiss (a high-grade metamorphic rock)

Zebra Jasper

Tumbled Opaque Chalcedony (SiO2)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3/FeO(OH) cementing agents)

Quartz Pebble (Iron-Stained)

Silicon Dioxide (SiO2)

Quartzite Cobble

Quartzite (SiO2)

Sandstone

Arenite (composed primarily of SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (with Goethite/Limonite cement)

Diorite (or salt-and-pepper granite pebble)

Phaneritic Igneous Rock (Intermediate Composition)

Limestone

Calcium Carbonate (CaCO3)

Sandstone (Ferruginous)

Arenite with Iron Oxide cement (SiO2 + Fe2O3)

Ferruginous Quartz (Iron-stained Quartz)

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Amygdaloidal Basalt

Amygdaloidal Basalt (extrusive volcanic rock with mineral inclusions)

Ocean Jasper

Silicon Dioxide (SiO2)

Quartzite

Quartzite (SiO2)

Oolitic Limestone

Oolite (Sedimentary Calcium Carbonate)

Agate (specifically, multi-colored or pastel-dyed agate)

Silicon dioxide (SiO2) - specifically, a cryptocrystalline variety of quartz known as Chalcedony, with banding classified as Agate. (If it were Fluorite, the chemical formula would be Calcium Fluoride - CaF2).

Chert (or Jasper)

Microcrystalline Quartz (SiO2)

Jasper

Silicon Dioxide (SiO2) with impurities

Petrified Wood

Silicified Wood (SiO2)

Jasper with Chert

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Petrified Wood

Silicified Wood (primarily Quartz/Chalcedony, SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Sapphire (likely blue synthetic sapphire or blue glass in a ring)

Corundum (Al₂O₃), specifically the blue variety due to trace amounts of iron and titanium impurities. If synthetic, it would still be Al₂O₃.

Diamond

Diamond (C)

Diamond

Diamond (C)

Chert

Chert (Microcrystalline Quartz, SiO2)

Chert (often called Flint)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Flint variety)

Silicon Dioxide (SiO2)

Chert Pebble

Chert (composed primarily of Microcrystalline Quartz, SiO2)

Chert (Chalcedony / Gray Flint)

Silicon Dioxide (SiO2)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint)

Chert (Silicon Dioxide, SiO2)