Mineral, Often Found As Detrital Grains In Sedimentary Rocks

Quartzite

Quartzite

Peridot

Olivine (specific variety: gem-quality forsterite), (Mg,Fe)2SiO4

Fuchsite Schist

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

Emerald

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

Quartzite

Quartzite (SiO2)

Agate

Silicon Dioxide (SiO2) - Chalcedony variety

Green Quartzite (Aventurine-like)

Quartzite (primarily SiO2 with trace Fuchsite mica inclusions)

Sandstone

Arenite (SiO2 predominantly)

River Cobble (likely Basalt or Metagraywacke)

Non-specific water-worn lithic fragment

Quartzite

Quartzite (primarily SiO2)

Granite Pebble

Granite (a plutonic igneous rock composed primarily of quartz, feldspar, and mica/amphibole)

Pyrite in Matrix (Commonly called Fool's Gold)

Iron Sulfide (FeS2)

Quartzite Pebble

Quartzite (SiO2)

Quartz (vein quartz)

SiO2 (Silicon Dioxide)

Quartzite

Quartzite (primarily SiO2)

Carnelian Agate

Chalcedony (SiO2 with Iron Oxide impurities)

Gneiss (with Quartzite and Mica)

Gneiss

Quartzite Pebble

Metamorphic Quartzite (primarily SiO2)

Quartzite

Quartzite (composed primarily of Quartz, SiO2)

Chert (specifically a Chert Nodule or Flint)

Cryptocrystalline Quartz (SiO2)

Banded Gneiss

Gneiss

Milky Quartz Geode or Druzy Quartz

Silicon Dioxide (SiO2)

Green Fluorite

Fluorite (Calcium Fluoride - CaF2)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Pyrite

Iron Sulfide (FeS2)

Quartzite pebble

Quartzite (SiO2)

Turquoise

Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]

Unidentified Rock Fragment

Unknown

Gemstone Sand (Mineral Assortment)

Mixed Mineral Concentrates (Commonly including Quartz SiO2, Garnet X3Y2(SiO4)3, and Tourmaline (Na,Ca)(Li,Mg,Al)3(Al,Fe,Mn)6(BO3)3(Si6O18)(OH,F)4)

Chert with Quartz Veining

Silicon Dioxide (SiO2)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Fluorite

Calcium Fluoride (CaF2)

Almandine Garnet

Almandine (Fe3Al2(SiO4)3)

Red Quartzite Cobble

Quartzite (primarily SiO2)

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrous ferric oxide)

Ironstone Concretion / Goethite-Hematite Nodule

Goethite/Hematite (α-FeO(OH) / Fe2O3)

Quartzite Pebbles

Quartzite (SiO2)

Muscovite Mica

Muscovite (Potassium Aluminum Silicate Hydroxide Fluoride), KAl2(AlSi3O10)(OH,F)2

Pyrite

Iron Sulfide (FeS2)

Turquoise (set in silver jewelry)

Turquoise - CuAl6(PO4)4(OH)8·4H2O (Hydrated copper and aluminum phosphate)

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Green Fluorite

Fluorite (Calcium Fluoride, CaF2)