Ironstone (with Limonite/Goethite)
Ferruginous Sedimentary Rock (contains Limonite FeO(OH)·nH2O and Hematite Fe2O3)
sedimentary
Category
Amorphous Solid
Browse amorphous solid specimens identified by the Rock Identifier community.
Obsidian
Volcanic Glass (70-75% SiO2 with MgO and Fe3O4)
igneous
Obsidian
Volcanic glass (high silica volcanic rock)
igneous
Anthracite Coal
Anthracite (high-rank coal / Carbon)
metamorphic
Tektite (likely Indochinite)
Tektite (high-silica impact glass)
igneous
Porphyritic Basalt (Chinese Writing Stone/Flower Stone)
Porphyritic Basalt (primarily Plagioclase Feldspar in a Mafic groundmass)
igneous
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
igneous
Sandstone Chert/Quartzite
Silicon Dioxide (SiO2) - Sedimentary Sandstone / Orthoquartzite
sedimentary
Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Obsidian
Obsidian (volcanic glass), predominantly Silicon Dioxide (SiO2)
igneous
Pumice
Pumice (Vesicular Volcanic Glass)
igneous
Obsidian
Obsidian (volcanic glass, amorphous silica rich rock)
Igneous
Blue Goldstone
Goldstone (artificial glass)
Mineral (man-made glass, not natural)
Slag (Industrial Byproduct)
Ferro-silicate glass (Slag)
Anthropogenic (Man-made industrial deposit)
Amber
Succinite (Resin C10H16O)
mineral
Laterite
Laterite (Ferricrete)
sedimentary
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Igneous
Precious Opal in Matrix
Hydrated Silica (SiO2·nH2O)
mineral
Obsidian (specifically Silver Sheen Obsidian)
Volcanic Glass (approx. 70–75% SiO2 plus MgO, Fe3O4)
igneous
Iron Slag
Anthropogenic Vitreous Ferrous Silicate
industrial byproduct (anthropogenic)
Ironstone Concretion / Limonite-stained Siltstone
Ironstone (primarily Limonite FeO(OH)·nH2O and Siltstone)
sedimentary
Jet
Lignite (Anthracite-grade compact coal)
sedimentary
Ferruginous Slag (Iron Smelting Byproduct)
Anthropogenic Vitreous Silicate (often containing Fayalite: Fe2SiO4)
Mineraloid/Anthropogenic (Technofossil)
Obsidian
Volcanic Glass (SiO2 rich)
Igneous
Obsidian
Obsidian (Volcanic Glass, SiO2)
igneous
Tektite (Indochinite)
Tektite (Natural Glass, SiO2 + Al2O3)
mineral
Limonite and Goethite (Ironstone)
Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)
sedimentary
Pumice
Extrusive volcanic rock (Vesicular Rhyolite/Dacite/Andesite)
igneous
Amber
Succinite (formula varies, primarily C10H16O)
Mineraloid (Organic)
Ironstone Concretion (Iron-rich Mudstone)
Siderite / Geothite concretion (FeCO3 / FeO(OH))
sedimentary
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Black Obsidian
Volcanic Glass (predominantly SiO2, Silicon Dioxide)
igneous
Ferrocoke or Slag
Anthropogenic pyrometallurgical residue
igneous
Obsidian
Obsidian (volcanic glass), primarily SiO2 (silicon dioxide)
igneous
Gossan (Iron Hat) with Quartz and Chlorite
Limonite/Goethite-rich Gossan (FeO(OH)·nH2O) with inclusions of Quartz and Chlorite
Mineral/Metamorphic Substrate
Iron Slag
Ferrous Slag (Silicate/Oxide mixture)
industrial byproduct (anthropogenic)
Amber
Succinite (a specific common type) or Fossilized Tree Resin (C10H16O)
Mineraloid
Moqui Marble (Shaman Stone)
Iron Oxide Concretion (composed primarily of Quartz sand with Hematite/Goethite shell)
sedimentary
Iron Slag
Iron Slag (Industrial Vitreous Material)
Mineral/By-product
Quartz (Water-worn pebble)
Silicon Dioxide (SiO2)
mineral
Concrete
Anthropogenic Sedimentary Rock (Hydrated Calcium Silicate)
sedimentary (anthropogenic / man-made)
Blue Goldstone
Aventurine Glass
Man-made glass (often grouped with minerals in lapidary)