Mineraloid (Impact Glass)

Obsidian

Obsidian (Extrusive Volcanic Glass)

Obsidian

Volcanic glass (mainly SiO2 with inclusions)

Obsidian

Amorphous volcanic glass (primarily SiO2)

Amber

Succinite

Polished black obsidian

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

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with impurities)

Obsidian (black volcanic glass), possibly slag or basalt

Obsidian; chiefly amorphous volcanic silica glass, approximately SiO₂-rich rhyolitic composition

Red cabochon gemstone, likely carnelian or dyed chalcedony

Chalcedony (microcrystalline quartz), SiO₂; exact identification requires testing

Black Obsidian

Volcanic Glass (SiO2 + impurities like Fe3O4)

Black Obsidian

Obsidian (Amorphous Silicon Dioxide)

Quartz Pebble (Beach Agate / Chalcedony Pebble)

Silicon Dioxide (SiO2)

Amber

Succinite (Fossilized Tree Resin)

Tumbled black obsidian (likely)

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

Snowflake Obsidian

Volcanic Glass with Spherulite inclusions (Chemical composition: 70–75% SiO2 + MgO, Fe3O4)

Opalite

Synthetic Glass (Amorphized Silicon Dioxide)

Amber

Succinite (approximate formula C10H16O)

Common Opal in Host Rock

Hydrated Silica (SiO2·nH2O)

Opalite

Man-made opalescent glass

Gold Sheen Obsidian

Volcanic Glass (SiO2 + impurities)

Obsidian

Amorphous volcanic glass (SiO2)

Black Obsidian

Obsidian (Volcanic Glass)

Opalite

Man-made synthetic glass with opalescent effects (SiO2 + metal oxides)

Green Opal or Yellow Opal

Hydrated Silica (SiO2·nH2O)

Amber

Succinite (Carbon-based organic compound; approximate formula C10H16O)

Fulgurite

Lechatelierite (Silica glass), typically SiO2

Polished black obsidian pyramid/block

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

Mahogany Obsidian

Volcanic Glass with Hematite inclusions

Black Obsidian

Volcanic Glass (Amorphous Silicon Dioxide)

Obsidian

Volcanic Glass (70-75% SiO2)

Amber

Succinates (C10H16O)

Snowflake Obsidian

Volcanic Glass (spherulitic Obsidian) - SiO2 (with Cristobalite inclusions)

Slag (Industrial Glass)

Anthropogenic Amorphous Vitreous Silicate

Obsidian arrowhead

Volcanic glass; predominantly SiO₂, with minor feldspar, pyroxene, and iron oxides

Obsidian

Volcanic glass (Amorphous silicon dioxide)

Amber

Succinite (with approximate formula C10H16O)

Amber with Inclusion

Succiniferous fossil resin (C10H16O)

Amber

Succinite (organic hydrocarbon)

Amber

Succinite (Resinous fossilized tree sap)

Obsidian

Volcanic Glass (SiO2)

Shungite

Shungite (carbon-rich Precambrian mineraloid)

Quartz Pebble

Silicon Dioxide (SiO2)

Rounded river pebble

Indeterminate lithic clast; likely weathered sandstone or quartz-rich sedimentary rock