Mineral, Often Found As Detrital Grains In Sedimentary Rocks

Amethyst on Agate/Basalt Matrix

Silicon Dioxide (SiO2) with iron impurities

Garnet in Schist (Polished Tower)

Almandine Garnet (Fe3Al2(SiO4)3) in Mica Schist

Petrified Wood

Silicified Wood (primarily SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Green Aventurine

Silicon Dioxide (SiO2) with Fuchsite inclusions

Turquoise

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

Quartz Geode with Goethite/Hematite

Silicon Dioxide (SiO2) with Iron Oxides

Vesicular Basalt (Scoria)

Vesicular Basalt

Ferruginous Quartz (Red Quartz)

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Limestone

Calcium Carbonate (CaCO3)

Turquoise

Hydrated phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O

Red Quartzite

Quartzite (primarily SiO2)

Chert (or possibly Flint)

SiO2 (Silicon Dioxide)

Pink Quartzite

Quartzite (primarily SiO2 with trace impurities of iron oxides)

Jade (likely Jadeite)

Jadeite (a pyroxene mineral) or Nephrite (a variety of amphibole mineral)

Green Calcite

Calcium Carbonate (CaCO3)

Black Sapphire

Corundum (Al2O3 with iron and titanium impurities)

Turquoise in Matrix

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

Sandstone (Banded)

Clastic Sedimentary Rock (primarily SiO2)

Rough Amber (likely Copal or immature Amber)

Organic gemstone / Succinite (if Baltic)

Granite Cobble

Phaneritic Felsic Igneous Rock

Amethyst

Silicon dioxide (SiO2) with iron impurities

Petrified Wood

Silicified Wood (SiO2)

Banded Chalcedony (Agate)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Psilomelane (Black Hematite/Manganese Ore)

Barium Manganese Oxide (Formula: BaMn9O18(OH)4)

Blue Kyanite

Kyanite (Al2SiO5)

Conglomerate

Clastic Sedimentary Rock (Conglomerate)

Limonite with Iron Inclusions

Limonite (Hydrated Iron Oxide, FeO(OH)·nH2O)

Gneiss

Gneiss

Aquamarine

Beryllium aluminum silicate (Be3Al2Si6O18)

Chert (Nodule)

Microcrystalline Silica (SiO2)

Crinoid and Coral Fossils in Limestone

Fossiliferous Limestone with Rugosa (order) and Crinoidea (class)

Rhodonite

Manganese Inosilicate (Mn,Fe,Mg,Ca)SiO3

Granodiorite with Biotite Mica

Granodiorite (containing Quartz, Plagioclase Feldspar, and Biotite Mica)

Diorite (Spotted or Dalmatian Stone pattern)

Diorite

Chert (Arrowhead Debitage or Flake)

Microcrystalline silica (SiO2)

Yellow Jasper

Silicon Dioxide (SiO2) with iron hydroxide impurities

Olivine (often within Peridotite)

Magnesium iron silicate, (Mg,Fe)2SiO4

Turquoise in Matrix

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

Fuchsite (Green Muscovite in Quartz)

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

Pyromorphite on Epidote

Pyromorphite [Pb5(PO4)3Cl] and Epidote [Ca2(Al2,Fe3+)(SiO4)3(OH)]

Quartz

Silicon dioxide (SiO₂)