Man Made Object (Coin)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with iron oxide staining/cementing)

Sandstone (likely a river or beach pebble)

Sandstone (a clastic sedimentary rock)

Sandstone (likely Quartzose)

Arenite (SiO2 principal mineral)

Granodiorite

Granodiorite (intermediate plutonic rock)

Chalcedony (Agate/Blue Quartzite)

Silicon Dioxide (SiO2)

Jasper

Silicon dioxide (SiO2)

Gold Nugget

Native Gold (Au)

Quartz (Clear/White)

Silicon Dioxide (SiO2)

Talc

Talc (Mg₃Si₄O₁₀(OH)₂)

Quartz (Milky/Iron-stained)

Silicon Dioxide (SiO2)

Sandstone (with Limonite staining)

Arenite (primarily SiO2 with FeO(OH)·nH2O)

Shale or Argillite

Shale (sedimentary) / Argillite (metamorphic)

Ironstone Concretion

Limonitic/Hematitic Concretion

Ironstone Nodule (Ironstone Concretion)

Siderite-rich Mudstone (FeCO3) or Limonite (FeO(OH)·nH2O)

Puddingstone (specifically Gowganda Tillite or St. Joseph Island Puddingstone)

Jasper Conglomerate

Strawberry Quartz (or Hematoid Quartz)

Silicon Dioxide (SiO2) with inclusions of Hematite or Goethite

Obsidian

Volcanic Glass (SiO2)

Red Sandstone

Arenite (primarily composed of SiO2 with Fe2O3 cement)

Jasper

Silicon dioxide (SiO2) with iron oxide inclusions

Pink Feldspar

Orthoclase Feldspar (KAlSi3O8)

Limestone

Calcium carbonate (CaCO3)

Sandstone (Quartz-rich)

Arenite (composed mainly of SiO2)

Jasper (Red/Yellow)

Silicon Dioxide (SiO2) with impurities

Red Jasper (with Quartz inclusions)

Silicon Dioxide (SiO2)

Amethyst Geode

Silicon Dioxide (SiO2) with trace Iron (Fe3+) impurities

Fluorite (Rainbow Fluorite)

Fluorite (Calcium Fluoride, CaF2)

Iron-Nickel Meteorite

Siderite (Meteoric Iron-Nickel alloy)

Hematite Nodule

Hematite (Fe2O3)

Green Fluorite

Fluorite (Calcium Fluoride - CaF2)

Ruby in Zoisite (Anyolite)

Anyolite (Combination of Corundum and Zoisite)

Granite (with Quartz and Mica)

Phaneritic Felsic Igneous Rock

Mica Schist

Mica Schist (primarily Muscovite or Biotite sheet silicates)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Ferruginous Sandstone (Red Sandstone)

Arenite with Hematite/Limonite cement

Jasper and Chert Conglomerate

Ferruginous Microcrystalline Quartz (SiO2)

Chalcedony (River Stone)

Silicon Dioxide (SiO2)

Dumortierite Quartz (Blue Quartz)

Al7BO3(SiO4)3O3 (Aluminum Boro-silicate included in Quartz)

Milky Quartz

Silicon Dioxide (SiO2)

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrous ferric oxide)

Red Jasper

Jasper (Silicon Dioxide, SiO2)

Serpentinite

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

Cat's Eye Shell (Shiva Shell)

Operculum of the Turbo petholatus (Tapestry Turban Snail), predominantly Calcium Carbonate (Aragonite)