Man Made Byproduct (Often Mistaken For Obsidian Or Emerald)

Emerald (Beryl)

Be₃Al₂Si₆O₁₈ (Chromium/Vanadium-bearing Beryl)

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide)

Sandstone

Arenite (SiO2 primarily)

Sandstone

Arenite (SiO2 composition dominant)

Chert (often called Flint for darker varieties)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Fuchsite (Chrome Mica)

K(Al,Cr)2(AlSi3O10)(OH)2

Diamond (in Jewelry)

Carbon (C)

Chalcopyrite

Chalcopyrite (CuFeS2)

Fuchsite

Cr-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2)

Emerald (Beryl)

Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities

Fuchsite

Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2)

Pearl

Aragonite / Calcium Carbonate (CaCO3)

Rough Emerald

Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)

Beryl (likely Emerald or Aquamarine in matrix)

Beryllium aluminum silicate (Be3Al2Si6O18)

Vesicular Rhyolite

Rhyolite (High-silica volcanic rock)

Fuchsite

K(Al,Cr)2(AlSi3O10)(OH)2

Chrysoprase

Silicon dioxide (SiO2) with nickel impurities

Peridot (Olivine)

Magnesium Iron Silicate (Mg,Fe)2SiO4

Fuchsite Schist

Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2) in Schist

Likely polished dark stone or glassy mineral bead

Indeterminate; possibly obsidian, hematite, or a dark agate

Polished black stone, likely obsidian

Volcanic glass; primarily silica-rich, noncrystalline SiO₂

Chert (Flint)

Silicon Dioxide (SiO2)

Greenstone

Greenschist

Diamond

Native Carbon (C)

Chalk

Micrite (primarily Calcium Carbonate or CaCO3)

Rough Emerald

Beryl (Be3Al2Si6O18 with Chromium and Vanadium impurities)

Fuchsite Schist

K(Al,Cr)2(AlSi3O10)(OH)2 (Chromium-rich Muscovite)

Chert / Green Jasper

Silicon Dioxide (SiO2)

Fuchsite

Chromium-bearing Muscovite - K(Al,Cr)2(AlSi3O10)(OH)2

Peridot

Olivine (Magnesium Iron Silicate - (Mg, Fe)2SiO4)

Dragon's Breath (Mexican Opal Glass)

Artisan Foil Glass (SiO2 based)

Sandstone

Arenite (composed primarily of SiO2)

Prase or Green Quartz

Silicon Dioxide (SiO2 with actinolite or chlorite inclusions)

Slag (Industrial Glass/Byproduct)

Anthropogenic Vitreous Silicate

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Fuchsite

Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2)

Chert (Iron-stained)

Microcrystalline Silica (SiO2)

Obsidian (Apache Tear)

Amorphous Volcanic Glass (SiO2 + impurities)

Asphalt Concrete (Bituminous Pavement)

Aggregates in Bitumen Matrix

Fuchsite or Green Mica Schist

K(Al,Cr)2(AlSi3O10)(OH)2

Concrete

Hydrated Portland Cement Aggregate Composite

Mahogany Obsidian

Volcanic glass (SiO2 with Hematite or Magnetite inclusions)