Man Made Object (Coin)

Quartz (variety of colors)

SiO2 (Silicon Dioxide)

Sandstone (River Rock)

Arenite (composed primarily of SiO2)

Talc

Talc (Mg₃Si₄O₁₀(OH)₂)

Sandstone (Quartz Sandstone)

Clastic sedimentary rock (primarily SiO2)

Chert Pebble (Jasper variant)

Microcrystalline Quartz (SiO2)

Scoria

Vesicular Basalt / Scoriaceous Basalt

Yellow Jade (Nephrite or Quartzite variety)

Ca2(Mg,Fe)5Si8O22(OH)2 (Nephrite) / SiO2 (Quartzite variant)

Yellow Jade

Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2) or Jadeite (NaAlSi2O6)

Greywacke (River Slikkenstone)

Greywacke (Impure Sandstone)

Jasper

Jasper (Silicon Dioxide, SiO2)

Granite

Phaneritic Plutonic Rock (High Silica content)

Fancy Jasper (Multicolor Agate/Jasper)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Aquamarine with Ruby Accent

Beryllium Aluminum Silicate (Be3Al2Si6O18) with Aluminum Oxide (Al2O3)

Blue Apatite

Apatite - Ca5(PO4)3(F,Cl,OH)

Milky Quartz

Silicon Dioxide (SiO2)

Sandstone

Arenite (composed primarily of SiO2)

Potassium Feldspar

Orthoclase (KAlSi3O8)

Fossilized Angel Wing Shell

Cyrtopleura costata

White Chalcedony (Agate)

Silicon Dioxide (SiO2)

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

Basalt

Basalt (Aphanitic Mafic Igneous Rock)

Sandstone (Ferruginous)

Arenite with Iron-Oxide Cement

Sandstone

Arenite (composed primarily of SiO2)

Sandstone

Arenite (Siliclastic sedimentary rock), SiO2 + various minerals

Sandstone (with manganese staining)

Clastic sedimentary rock (primarily SiO2)

Sandstone (Weathered Cobble)

Clastic Sedimentary Rock (primarily SiO2)

Limestone with Calcite Crystals

Calcium Carbonate (CaCO3)

Granite Cobble

Felsic Intrusive Igneous Rock (composed of Quartz, Alkali Feldspar, and Plagioclase)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Ferruginous Sandstone (Ironstone)

Arenite with Iron-Oxide Cement (FeO(OH)·nH2O / Fe2O3)

Blue Quartzite (Aventurine)

Quartzite (primarily SiO2) with inclusions of Dumortierite or Magnesio-riebeckite

Sandstone (with Iron Staining)

Clastic Sedimentary Rock (primarily SiO2 with Fe2O3 oxides)

Cinnabar in Quartz

Silicon Dioxide (SiO2) with Mercury Sulfide (HgS) inclusions

Ammonite Fossil

Ammonoidea (primarily composed of Calcite, CaCO3)

Aquamarine and clear quartz

Aquamarine (Be3Al2Si6O18), Quartz (SiO2)

Yellow Quartz (Citrine/Yellow Jasper mix)

Silicon Dioxide (SiO2)

Blue Sapphire (faceted in jewelry)

Corundum (Al2O3)

Yellow Quartzite Pebble

Quartzite (primarily Silicon Dioxide - SiO2)

Rainbow Fluorite

Fluorite (Calcium Fluoride, CaF2)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Amazonite (or Amazon Stone)

Potassium Feldspar (Microcline), K(AlSi3O8)

Cockle Shell (Fossil or Recent)

Class Bivalvia, Family Cardiidae (e.g., Cerastoderma edule for common cockle)