Anthracite Coal
Anthracite
Category
Browse amorphous solid specimens identified by the Rock Identifier community.
Anthracite Coal
Anthracite
Dzi Bead Bracelet with Agate and Obsidian
Chalcedony (SiO2) and Volcanic Glass (SiO2 + impurities)
Amber (Tumbled/Polished)
Succinite (Fossilized Tree Resin)
Obsidian Jewelry Piece
Volcanic Glass (SiO2 + impurities)
Anthracite Coal
Anthracite (Carbon-rich metamorphic coal)
Gossan
Ferruginous gossan (Iron-rich capping)
Pumice
Pumice (Vesicular Rhyolite/Andesite)
Obsidian
Volcanic Glass (mostly SiO2)
Limonite (Ironstone)
Limonite (FeOO·nH2O)
Tektite (Indochinite)
Tektite (High-silica natural glass)
Snowflake Obsidian
Volcanic glass containing Spherulitic inclusions (SiO2 + impurities)
Black Obsidian
Volcanic Glass (SiO2)
Chrysocolla
Hydrated copper silicates (Cu, Al)2H2Si2O5(OH)4·nH2O
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
Limonite (Yellow Ochre)
Hydrated iron(III) oxide-hydroxides (FeO(OH)·nH2O)
Amber (Burmite)
Fossilized tree resin (Succinite variant)
Ironstone Concretion (Limonite/Goethite)
Iron oxide concretion (contains FeO(OH)·nH2O)
Ironstone Concretion (Limonite/Goethite)
Ironstone (composed primarily of Goethite FeO(OH) and Limonite)
Black Obsidian
Volcanic Glass (SiO2 + impurities)
Fossilized Crab Carapace (Concretion)
Decapoda (fossil), typically preserved in calcite or siderite concretion
Amber
Succinite (C10H16O)
Apache Tear (Obsidian)
Volcanic glass (SiO2 - Silicon Dioxide)
Amber
Succinite (fossilized resin)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
Yellow Ochre / Limonite
Limonite (FeO(OH)·nH2O)
Limonite (Iron Stone Concretion)
Limonite (Hydrous Iron Oxide) - FeO(OH)·nH2O
Black Opal
Hydrated Silica (SiO2·nH2O)
Mahogany Obsidian
Volcanic Glass with Hematite inclusions (SiO2)
Precious Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
Obsidian
Obsidian (Volcanic Glass)
Bumble Bee Jasper
Calcite-bearing Volcanic Tuff (not a true Jasper)
Anthracite Coal
Anthracite (high-rank coal)
Obsidian
Volcanic Glass (SiO2)
Obsidian
Volcanic Glass (SiO2)
Anthracite Coal
Anthracite
Chrysocolla
Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4·n H2O)
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Limonite Concretion (Ironstone)
Limonite (FeO(OH)·nH2O) with Goethite and Hematite
White Opal
Hydrated Silica (SiO2·nH2O)
Obsidian
Obsidian (Volcanic Glass)
Leopard Skin Jasper
Rhyolite (Silicon Dioxide with impurities), SiO2
Obsidian
Obsidian (principally SiO2 + MgO, Fe3O4)