Mineral, Often Found As Detrital Grains In Sedimentary Rocks

Sandstone (likely Graywacke or Lithic Sandstone)

Arenite / Wacke (SiO2 based with lithic fragments)

Mica Schist

Mica Schist

Ironstone Concretion

Siderite or Hematite-bonded Concretion

Gneiss (specifically Granite Gneiss)

Gneiss (High-grade Regional Metamorphic Rock)

Sandstone Concretion

Clastic sedimentary rock (primarily Silica, SiO2, or Calcium Carbonate, CaCO3)

Sand (Construction Grade)

Unconsolidated siliciclastic sediment (primarily SiO2)

Sandstone (Quartzose Sandstone Pebble)

Arenite (primarily SiO2)

Sandstone with Quartz Veining

Clastic sedimentary rock (SiO2 dominated)

Olivine (Peridot)

Olivine (Mg, Fe)2SiO4

Sandstone (Water-worn)

Arenite

Quartz (Milky or Citrine-leaning)

Silicon Dioxide (SiO2)

Sandstone Concretion

Ferruginous Sandstone Concretion (Primarily SiO2 with Iron Oxide cement)

Sandstone (Ferruginous)

Arenite with Iron Oxide cement

Banded Gneiss (with Quartz Vein)

Gneiss (Metamorphic rock of varying mineralogy)

Micaceous Sandstone or Quartzite

Sandstone (lithified quartz grains, often with mica) or Quartzite (metamorphosed sandstone)

Garnet (likely Almandine)

Almandine (Fe3Al2(SiO4)3)

Red Sandstone

Arenite (Ferruginous Sandstone)

Sandstone Beach Pebble

Clastic Sedimentary Rock (primarily Quartz with Iron Oxide coating)

Sandstone (Quartzose Sandstone)

Arenite (SiO2 principal component)

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Sandstone

Sandstone (lithified arenite/wacke)

Sandstone (Muddy/Silty Variety)

Arenite with high silt/clay content (clastic sedimentary rock)

Sandstone (specifically Red Sandstone)

Arenite (primarily Quartz, SiO2)

Banded Gneiss

Gneiss (Metamorphic Rock)

Sandstone (specifically Picture Sandstone or Wonderstone)

Arenite (composed primarily of SiO2)

Sandstone

Arenite (SiO2 based clastic rock)

Quartzite (Yellow/Iron-stained Quartz)

Quartzite (primarily SiO2 with iron oxide impurities)

Limonite (Iron Ore/Hydrated Iron Oxide)

Limonite (mixture of FeO(OH)·nH₂O minerals, mainly Goethite, FeO(OH) and Lepidocrocite, FeO(OH))

Schist

N/A (a rock type, not a mineral formula)

Sandstone (Quartzite-rich Cobble)

Clastic sedimentary rock (primarily SiO2)

Sandstone (Ferruginous)

Arenite with Iron Oxide (Limonite/Hematite) coating

Red Sandstone

Arenite (Fe2O3 rich)

Mica Schist

Mica Schist

Quartzite

Quartzite (primarily SiO2)

Sandstone

Arenite (SiO2 based)

Sandstone

Arenite (SiO2 based with mineral cement)

Gneiss (Metamorphic Rock)

Gneiss

Rough Gemstone Grains (Mixed Sapphires and Quartz)

Corundum (Al2O3) and Quartz (SiO2)

Greenstone

Metamorphosed Mafic Igneous Rock

Sandstone

Arenite (composed primarily of SiO2)

Olivine (Peridot)

Magnesium Iron Silicate (Mg,Fe)2SiO4

Biotite or Phlogopite Mica

K(Mg,Fe)3(AlSi3O10)(F,OH)2