Industrial Byproduct (Often Mistaken For Obsidian Or Mineral)

Dendritic Limestone

Calcite with Manganese Oxide (Manganese Dendrites)

Dendrite (Manganese Oxide Dendrites)

Psilomelane or Pyrolusite on Matrix (typically MnO2)

Milky Quartz with Dendritic Inclusions

Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurity)

Obsidian

Obsidian (principally SiO2 + MgO, Fe3O4)

Sodalite

Na8(Al6Si6O24)Cl2

Mahogany Obsidian

Volcanic Glass (with inclusions of Magnetite or Hematite)

Chrysoprase

Chalcedony (Silicon Dioxide, SiO2), flavored by Nickel

Dumortierite Quartz

Al7BO3(SiO4)3O3 (Aluminum borate silicate)

Pyrite

Iron Sulfide (FeS2)

Dalmation Stone (Dalmation Jasper)

Peralkaline rock (primarily Feldspar and Quartz with Arfvedsonite spots)

Mahogany Obsidian

Obsidian (Volcanic Glass) with Hematite/Magnetite inclusions

Limonite Concretion (Ironstone)

Limonite (FeO(OH)·nH2O) / Goethite

Mahogany Obsidian

Volcanic glass containing Magnetite/Hematite

Ironstone Concretion

Siderite or Ferruginous Concretion (FeCO3 or Iron Oxides)

Apache Tear

Obsidian (Hydrated Volcanic Glass - SiO2)

Ironstone Concretion (Pot Stone)

Siderite or Limonite Concretion (FeCO3 or FeO(OH)·nH2O)

Ambergris

Ambra grisea (Metabolic byproduct)

Sandstone Concretion

Ferruginous Sandstone Concretion

Felted Quartz / Chlorite Quartz

Chlorite included Quartz (SiO2 + (Mg,Fe)3(Si,Al)2O5(OH)4)

Ferruginous Quartz (Iron-Stained Quartz)

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Obsidian

Volcanic Glass (Amorphous Silica)

Obsidian

Amorphous volcanic glass (70-75% SiO2)

Sandstone Concretion

Arenaceous concretion (primarily SiO2 with Fe2O3 staining)

Fuchsite

Chromium-rich Muscovite (KAl2(AlSi3O10)(OH,F)2 with Cr replacements)

Green Chalcedony (likely Chrysoprase or Green Onyx)

Silicon Dioxide (SiO2) with trace nickel or chromium inclusions

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

Obsidian

Volcanic Glass (SiO2 rich)

Diorite (Salt and Pepper Rock)

Diorite

Dumortierite Quartz

Dumortierite (Al7BCuO15)

Obsidian

Obsidian (Volcanic Glass)

Golden Sheen Obsidian

Obsidian (volcanic glass) with inclusions of gas bubbles and mineral crystals (e.g., hematite, magnetite) causing the sheen

Snowflake Obsidian

Vitreous volcanic silicate (SiO2 with Cristobalite inclusions)

Mahogany Obsidian

Volcanic Glass (predominantly SiO2 with Fe2O3 inclusions)

Red Quartz (Ferruginous Quartz)

Silicon Dioxide with Hematite inclusions (SiO2 + Fe2O3)

Sodalite

Sodalite [Na8(Al6Si6O24)Cl2]

Pyrite with Iron Oxides (Fool's Gold in Matrix)

Iron Sulfide (FeS2)

Sandstone Concretion

Sandstone (Sedimentary Rock) with silica or calcite cement

Obsidian

Obsidian (Volcanic Glass, complex silicate)

Black Obsidian

Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)

Obsidian

Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)

Apache Tears (Obsidian)

Hydrated Volcanic Glass (Amorphous SiO2 + H2O)