Anthracite Coal
Low-grade metamorphic carbonaceous rock
metamorphic
Category
Amorphous Solid
Browse amorphous solid specimens identified by the Rock Identifier community.
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Anthracite Coal
Anthracite (Carbon Content: 86%–98%)
metamorphic
Ferro-Manganese Slag
Vitreous Silicate Slag
Anthropogenic (Industrial byproduct)
Amber
Succinite
mineraloid
Obsidian
Volcanic Glass (70-75% SiO2)
igneous
Moqui Marble (Shaman Stone)
Ironstone Concretion (Fe2O3) - primarily Hematite or Goethite shell with Sandstone core
sedimentary
Limonite (Ironstone)
Limonite (FeO(OH)·nH2O)
mineral
Obsidian Arrowhead
Volcanic Glass (70% or more SiO2)
Igneous
Naga Silver-Inlaid Ebony and Bone/Horn Beads
Diospyros (Ebony) or Keratin (Horn) with Silver/White-Metal Inlay
Organic (Anthropological Artifact)
Gossan with Copper Carbonate (Chrysocolla/Malachite)
Ferruginous Oxide (Gossan) with Cu2CO3(OH)2 (Malachite) or (Cu,Al)2H2Si2O5(OH)4 (Chrysocolla)
Mineral/Sedimentary Interface
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurity)
Igneous
Opalite
Synthetically produced glass (Silicon Dioxide with metallic inclusions)
Mineraloid (Man-made Glass)
Opalite
Synthetic Glass, SiO2 base with metallic inclusions
mineraloid (synthetic)
Black Obsidian
Volcanic Glass (SiO2 + impurities)
igneous
Opalite (Man-made Glass)
Synthetic Opalised Glass
mineral
Obsidian
Obsidian (principally SiO2/Silicon dioxide)
igneous
Anthracite Coal
Anthracite (Carbon-based sedimentary rock typically classified as metamorphic)
metamorphic
Chrysocolla
Chrysocolla - (Cu,Al)2H2Si2O5(OH)4·nH2O
mineral
Fossiliferous Limestone (Chert/Clay mixed)
Calcium Carbonate (CaCO3) / Silicon Dioxide (SiO2)
sedimentary
Lignite (Brown Coal)
Humic Lignite (Carbonaceous sedimentary rock)
sedimentary
Pumice
Pumice (Vesicular Rhyolite/Andesite)
igneous
Mahogany Obsidian or Red Jasper
Silicon Dioxide with Iron Oxide (SiO2+Fe2O3)
Mineral/Igneous (Volcanic Glass)
Amber
Succinite (specifically for Baltic amber); C10H16O (Variable organic compound)
mineral
Limonite (Iron Ore)
Limonite (Hydrous ferric oxides), generic formula FeO(OH)·nH2O
mineral
Red Sandstone (Iron-rich Sandstone)
Clastic Sedimentary Rock - Quartz Arenite / Arkose with Hematite Cement
sedimentary
Moqui Marble (Shaman Stone)
Iron Oxide Concretion (Hematite/Goethite shell with Sandstone core)
sedimentary
Mahogany Obsidian
Volcanic Glass (SiO2 + Fe2O3)
igneous
Coquina / Limonite-stained Limestone
Sedimentary Limestone with Iron Oxyhydroxide (FeO(OH)·nH2O)
sedimentary
Amber
Succinite (Fossilized Resin C10H16O)
Organic Mineraloid
Obsidian
Volcanic Glass (SiO2)
igneous
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurity isotopes)
igneous
Petrified Wood
Silicified Wood (SiO2)
mineral
Silver Sheen Obsidian
Volcanic Glass (Amorphous Silicon Dioxide - SiO2 with impurities)
igneous
Slag
Ferrous slag (by-product of iron smelting)
Mineraloid / Anthropogenic
Opalite
Synthetic Opalized Glass / Man-made Glass
gemstone
Pumice
Pumice (a highly vesicular amorphous volcanic glass)
igneous
Tektite (Indochinite)
Tektite (Amorphous silica glass, SiO2 with impurities)
meteorite
Polished amber
Amber (fossilized plant resin), commonly succinite; organic mineraloid rather than a true mineral
gemstone
Petrified Wood
Silicified Wood (SiO2)
fossil
Amber
Fossilized tree resin
gemstone
Petrified Wood
Silicified Wood (SiO2)
fossil
Goldstone (blue-goldstone–style glass) beads
Artificial aventurine glass, typically silica glass with copper inclusions; not a natural mineral
mineral