Synthetic (Man Made Material Mimicking Natural Stone)

Schist

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

Apache Tear (Obsidian)

Obsidian / Amorphous Volcanic Glass (primarily SiO2)

Jasper (specifically Yellow Jasper and Red Jasper)

Silicon Dioxide (SiO2) with iron oxide inclusions

Diamond

Carbon (C), specifically in an isometric crystal system.

Citrine Quartz

Silicon Dioxide (SiO2) with iron impurities

Sandstone (Ferruginous)

Clastic Sedimentary Rock (primarily SiO2 with Fe2O3 staining)

Yellow Calcite

Calcium Carbonate (CaCO3)

Chert (variations include Flint or Jasper)

Chert (SiO2)

Quartzite

Quartzite (primarily SiO2)

Serpentine (Serpentinite)

Serpentinite (complex silicate group including lizardite, chrysotile, and antigorite)

Diamond

C (Carbon)

Clear Quartz

SiO2 (Silicon Dioxide)

Green Moss Agate

Silicon Dioxide with inclusions (SiO2)

Sandstone (with manganese staining)

Clastic sedimentary rock (primarily SiO2)

Chert / Flint

Silicon Dioxide (SiO2)

Serpentinite

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

Serpentinite (often called Jade or Nephrite substitute)

Serpentinite (composed primarily of Antigorite, Lizardite, or Chrysotile)

Banded Calcite (often sold as 'Mexican Onyx')

Calcite (Calcium Carbonate - CaCO3)

Sandstone (likely Graywacke or Arkose variant)

Clastic Sedimentary Rock (Lithic Sandstone)

Pink Rhodonite

Manganese Silicate (MnSiO3)

Chert / Jasper

Microcrystalline Quartz (SiO2)

Serpentinite

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

Chert (Flint nodule)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Rhodonite Tumbled Chips

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

Chert (often called Flint)

Chert (Cryptocrystalline Silica, SiO2)

Red Sandstone

Arenite (Ferruginous Sandstone)

Limonitic Iron Ore / Goethite

Hydrated Iron(III) oxide-hydroxide (primarily FeO(OH)·nH2O)

Chert (Chert Nodule)

Microcrystalline quartz (SiO2)

Green Jasper

Jasper (Silicates, SiO2)

Red Sandstone

Clastic Terrigenous Sedimentary Rock (typically Hematitic Quartz Arenite or Arkose)

Green Chalcedony (likely Chrysoprase or dyed Green Agate)

Silicon Dioxide (SiO2) with nickel impurities or chromium/dye

Green Aventurine

Aventurine Quartz (SiO2 with Fuchsite inclusions)

Quartzite

Quartzite (SiO2)

Amethyst (Agate/Chalcedony variety)

Silicon Dioxide (SiO2) with iron impurities

Emerald

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

Quartzite

Metamorphic Quartzite (SiO2)

Red Sandstone

Arenite (Fe2O3 rich)

Iron-stained Quartz

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Fossiliferous Limestone (Coquina / Shell Limestone)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Sandstone (likely Arkose)

Arenite (Feldspathic Sandstone / Arkose)

Red Quartzite

Quartzite (primarily SiO2)

Sandstone (likely Quartzose Sandstone)

Arenite (primarily SiO2)