Pumice
Pumice (Vesicular Rhyolite/Andesite)
Category
Browse amorphous solid specimens identified by the Rock Identifier community.
Pumice
Pumice (Vesicular Rhyolite/Andesite)
Lignite (Brown Coal)
Humic Lignite (Carbonaceous sedimentary rock)
Silver Sheen Obsidian
Volcanic Glass (Amorphous Silicon Dioxide - SiO2 with impurities)
Amber
Succinite (C10H16O)
Coquina
Biogenic Limestone (Coquina)
Anthracite Coal
Anthracite (Carbon-based metamorphic rock)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Anthracite Coal
Anthracite (Carbon-based organic sedimentary rock transitioned to metamorphic)
Tektite (Indochinite)
Tektite (High-silica natural glass)
Green glass sphere/marble
Soda-lime glass (primarily SiO2, Na2O, CaO)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (70% or more silicon dioxide)
Snowflake Obsidian
Volcanic glass containing Spherulitic Cristobalite (SiO2)
Amber
Succinite (fossilized resin)
Ironstone Concretion
Siderite or Hematite Concretion
Ambergris
Ambergris (Coprolite-adjacent/Organic secretion)
Limonite (Iron Ore)
FeO(OH)·nH2O (Hydrous ferric oxide)
Amber
Succinite
Fire Opal (in Matrix)
Hydrated Silica (SiO2·nH2O)
Limonite with Opal infusion
FeO(OH)·nH2O (Limonite) / SiO2·nH2O (Opal)
Tektite (Indochinite)
Tektite (High-silica natural glass, primarily SiO2 with Al2O3)
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Rough Amber (likely Copal or immature Amber)
Organic gemstone / Succinite (if Baltic)
Ferrochrome Slag
Industrial Glassy Slag (Fe-Cr alloy byproduct)
Obsidian
Obsidian (principally SiO2)
Slag (Industrial Byproduct)
Ferrous/Non-ferrous Silicate
Black Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Anthracite Coal
Anthracite (a form of coal, primarily carbon)
Obsidian
Volcanic glass (mainly SiO2 with inclusions)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)
Dendritic Opal
Hydrated Silica with Manganese inclusions (SiO2·nH2O)
Amber
Succinite (fossilized tree resin)
Amber
Succinite (Resinite), C10-H16-O
Obsidian and Green Calcite
Volcanic Glass and Calcium Carbonate (CaCO3)
Ambergris (Sea Wax)
Physeter macrocephalus fecalith
Obsidian
Volcanic Glass (Extrusive Igneous Rock, primarily SiO2)
Mahogany Obsidian
Volcanic glass containing Hematite or Magnetite (SiO2 + Fe2O3)
Ferrosilicon Slag (Industrial Vitrified Glass)
Vitreous Silicate Residue
Quartz / Common Opal
Silicon Dioxide (SiO2)
Obsidian
Obsidian (Volcanic Glass)
Bauxite
Bauxite (Mixture of Hydrous Aluminum Oxides)
Anthracite Coal
Anthracite