Metamorphic Rock

Gneiss (specifically a weathered Amphibolite or Garnet Gneiss)

Gneiss (complex silicate composition)

Green Schist

Greenschist (composed of Chlorite, Actinolite, and Epidote)

Yellow Quartzite (River Cobble)

Quartzite (mainly SiO2)

Tiger's Eye (Rough)

Pseudomorph of Quartz after Crocidolite (SiO2)

Quartzite

Quartzite (SiO2)

Blue Sapphire

Corundum (Al2O3)

Gneiss

Gneiss

Limonite (Iron Ore)

Limonite (an amorphous mixture of hydrated iron oxides, primarily FeO(OH)·nH2O)

Amethyst

SiO2 (Silicon Dioxide with Iron impurities and natural radiation influence)

Quartz (Milky or Common Quartz)

Silicon Dioxide (SiO2)

Asphalt (Bituminous Concrete)

Bituminous Concrete / Pavement

Quartzite Pebble

Quartzite (predominantly Silicon Dioxide - SiO2)

Serpentinite

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

Quartz (likely a form of massive or vein quartz)

Quartz (SiO₂)

Moonstone

Orthoclase Feldspar (composed of alternate layers of orthoclase and albite), (K,Na)AlSi3O8

Blue Sapphire

Corundum (Al2O3) with traces of Iron and Titanium

Agate

Silicon Dioxide (SiO2) - Chalcedony variety

Pyrite in Quartz

Iron Sulfide (FeS2) in Silicon Dioxide (SiO2)

Granitic Pegmatite

Granitic Pegmatite with Quartz and Feldspar

Gneiss (Granitic Gneiss)

Gneiss (from German Gneis, related to 'spark')

Dragon Blood Jasper

Epidote with Red Jasper inclusions (SiO2 and Ca2(Al,Fe)3(SiO4)3(OH))

Serpentine

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

Gneiss

Gneiss

Emerald In Matrix

Beryl (Be3Al2Si6O18) with trace Chromium/Vanadium

Serpentinite

Serpentinite (composed primarily of serpentine group minerals like lizardite, chrysotile, or antigorite; Mg3Si2O5(OH)4)

Greenstone

Greenschist (metamorphosed mafic igneous rock)

Quartzite with inclusions

Metamorphosed Quartz-rich Rock (SiO2)

Schist

Mica Schist (predominantly Muscovite or Biotite)

Yellow Quartzite (River Pebble)

Quartzite (mainly SiO2)

Yellow Quartzite (River Stone)

Quartzite (primarily SiO2)

Quartzite (specifically a river-worn cobble)

Quartzite (primarily Silicon Dioxide, SiO2)

Quartzite with Iron Hydroxide Staining

Quartzite (primarily SiO2) with Limonite/Goethite staining

Serpentinite

Serpentinite (containing minerals of the Serpentine subgroup: Antigorite, Lizardite, and Chrysotile; formula (Mg,Fe)3Si2O5(OH)4)

Schist

Mica Schist

Lapis Lazuli

Na8(Al6Si6O24)S2 (composed primarily of Lazurite, Calcite, and Pyrite)

Quartzite Pebble

Quartzite (primarily SiO2)

Quartzite Pebble

Quartzite (SiO2)

Quartzite with Quartz Vein

Quartzite (SiO2)

Magnetite (potentially as a Lodestone or within Ironstone)

Magnetite (Fe3O4)

Gneiss (specifically a Granitic Gneiss)

Gneiss (typically composed of Quartz, Feldspar, and Mica/Amphiboles)

Quartzite

Quartzite (SiO2)

Yellow Quartzite

Metamorphosed Quartz (SiO2)