Quartzite with Quartz Veins
Quartzite (chiefly SiO2)
metamorphic
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Chert (Brecciated Chert)
Silicon Dioxide (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Quartz Vein in Host Rock
Silicon Dioxide (SiO2)
mineral / metamorphic
Quartzite with Iron Hydroxide Staining
Quartzite (primarily SiO2) with Limonite/Goethite staining
metamorphic
Tiffany Stone
Fluorite Opal (a complex mix of Fluorite, Opal, Calcite, Dolomite, Quartz, and Bertrandite)
mineral
Granodiorite / Granite
Granodiorite (containing Quartz SiO2, Plagioclase Feldspar, and Biotite)
igneous
Limestone
CaCO3 (Mainly Calcite or Aragonite)
sedimentary
Pearl (incorporated into jewelry)
Aragonite and Calcite (CaCO3)
mineral
Granite
Phaneritic Acidic Igneous Rock (Granite Group)
igneous
Granite
Granite
igneous
Chert (often called Flint)
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Aquamarine
Beryllium aluminum silicate (Be3Al2Si6O18)
mineral
Diamond (as set in a gold ring)
Carbon (C)
mineral
Aquamarine
Beryl (Be₃Al₂Si₆O₁₈)
mineral
Quartz with Iron Staining
Silicon Dioxide (SiO2) with iron oxide impurities
mineral
Aquamarine
Beryl (Be₃Al₂Si‑₆O₁₈)
mineral
Onyx
Chalcedony (SiO2) with parallel banding
mineral
Diorite
Phaneritic intermediate plutonic rock
igneous
Black Onyx
Silicon Dioxide (SiO2)
mineral
Garnet
Garnet Group (Silicate mineral); general formula X3Y2(SiO4)3
mineral
Mica Schist with Pyrite
Muscovite/Biotite Schist (Complex Silicate)
metamorphic
Smoky Quartz
Silicon Dioxide (SiO₂)
mineral
Geode with Quartz Crystal Cavity
Silicon Dioxide (SiO2) in Calcareous/Siliceous Matrix
sedimentary
Basalt
Extrusive mafic igneous rock
igneous
Diabase (also known as Dolerite)
Diabase / Microgabbro
igneous
Gneiss
Gneiss
metamorphic
Pyrite
Iron Sulfide (FeS2)
mineral
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Diabase
Diabase (also known as Dolerite)
igneous
Quartz in Matrix (possibly with Biotite or Hornblende)
Quartz (Silicon Dioxide, SiO2) in Granitic Matrix
igneous
Lunar Highlands Breccia (Meteorite)
Lunar Feldspathic Breccia
igneous
Lunar Feldspathic Breccia
Lunar Meteorite (Feldspathic Regolith Breccia)
igneous
Porphyritic Basalt (Leopard Rock)
Porphyritic Mafic Volcanic Rock
igneous
Porphyritic Basalt
Porphyritic Basalt (containing Plagioclase or Alkali Feldspar phenocrysts)
igneous
Lunar Meteorite (Feldspathic Breccia)
Achondrite, Lunar Meteorite (Feldspathic Breccia)
igneous
Lunar Meteorite (Feldspathic Breccia)
Lunar Achondrite (Regolith Breccia)
igneous
Granite
Phaneritic Felsic Igneous Rock (Granite)
igneous
Unakite
Epidotized Granite
metamorphic
Unakite
Epidotized Granite
metamorphic
Blue Quartzite
Quartzite with inclusions (SiO2)
metamorphic