Mineral (Or Mineraloid If Microcrystalline)

Mahogany Obsidian

Obsidian (Volcanic Glass with Hematite/Magnetite inclusions), SiO2

Obsidian

Obsidian (volcanic glass; primarily SiO2)

Obsidian

Volcanic glass (high silica volcanic rock)

Obsidian

Volcanic Glass (70-75% SiO2 with MgO and Fe3O4)

Black Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Polished black obsidian pyramid/block

Obsidian — natural volcanic glass, chiefly rhyolitic silica (approximately 70–75% SiO₂)

Obsidian

Volcanic glass (mainly SiO2 with inclusions)

Snowflake Obsidian

Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)

Snowflake Obsidian

Volcanic Glass with Cristobalite inclusions (70–75% SiO2)

White Opal

Hydrated Silica (SiO2·nH2O)

Black obsidian

Volcanic glass; predominantly rhyolitic silica glass (approximately 70–80% SiO₂)

Black Obsidian

Amorphous volcanic glass (SiO2)

Obsidian (specifically Mahogany Obsidian)

Volcanic glass (high silica content, SiO2)

Tumbled mahogany obsidian

Volcanic glass; primarily SiO₂ with iron-oxide-rich brown inclusions

Obsidian

Obsidian (Volcanic Glass; SiO2 content > 70%)

Mahogany Obsidian

Volcanic Glass (SiO2 + Fe2O3)

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Limonitic Iron Ore / Goethite

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

Amber (Black)

Amber (succinite, retinite, etc., specifically, heavily included/dark varieties)

Obsidian (likely black volcanic glass)

Obsidian; predominantly silica-rich rhyolitic volcanic glass (approximately 70– on 80% SiO₂)

Polished black obsidian

Volcanic glass, predominantly rhyolitic silica (SiO₂)

Likely obsidian fragment

Volcanic glass, predominantly silica-rich rhyolitic composition (SiO₂-rich)

Obsidian (likely Apache tear or flaked obsidian)

Volcanic glass; primarily rhyolitic silica glass (SiO₂-rich, non-crystalline)

Mahogany Obsidian

Obsidian (Volcanic Glass with Hematite inclusions)

Gold Sheen Obsidian

Volcanic Glass (SiO2 + impurities)

Mahogany Obsidian

Volcanic glass (SiO2 with Hematite/Magnetite inclusions)

Polished mahogany obsidian (likely)

Volcanic glass; primarily silica-rich rhyolitic glass (SiO₂), with iron oxides

Snowflake Obsidian

Volcanic Glass with Spherulite Inclusions (primarily SiO2)

Obsidian

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

Obsidian

Obsidian (Volcanic Glass, SiO2)

Snowflake Obsidian

Volcanic glass with Cristobalite inclusions (mostly SiO2)

Limonite (with Pyrite)

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

Obsidian

Volcanic Glass (SiO2 rich)

Snowflake Obsidian

Volcanic Glass (SiO2) with Cristobalite inclusions

Polished black obsidian

Volcanic glass; primarily silica-rich rhyolitic glass (approximately 70–80% SiO₂)

Polished black obsidian

Volcanic glass; primarily silica-rich rhyolitic composition (approximately 70–80% SiO₂)

Black obsidian

Volcanic glass; predominantly rhyolitic silica-rich melt (approximately 70–80% SiO₂), lacking crystalline structure

Obsidian (likely snowflake-free black variety)

Volcanic glass; primarily SiO₂-rich rhyolitic composition

Black Obsidian

Obsidian (Volcanic Glass, ~70% SiO2)

Snowflake Obsidian (Flower Jasper variant)

Vitreous volcanic silicate with cristobalite inclusions

Mahogany Obsidian

Volcanic Glass (Silicate: SiO2 + Fe2O3)

Abalone Shell (Nacre)

Aragonite (CaCO3) - Biogenic Mineral