Obsidian
Volcanic Glass (Amorphous silicon dioxide with trace impurities)
igneous
Category
Amorphous Solid
Browse amorphous solid specimens identified by the Rock Identifier community.
Learn about Amorphous Solid in the encyclopedia
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Opalite
Synthetic Glass (Simulated Moonstone/Opal)
gemstone
Opalite (Man-made Glass)
Synthetic Silicon Dioxide Glass (SiO2 + metal oxides)
Synthetic Mineral Simulant / Glass
Opalite
Man-made Glass (Synthetic Opalized Glass)
mineral
Olivine (likely Peridot variety)
Olivine Mineral Group (specifically Forsterite-Fayalite solid solution series); Chemical formula: (Mg,Fe)2SiO4
Mineral
Diamond
Carbon (C), specifically a solid form of the element carbon with atoms arranged in a crystal structure called diamond cubic.
Mineral
Tumbled Obsidian (possibly Mahogany Obsidian variant)
Volcanic Glass (Amorphous Silicon Dioxide, SiO2)
igneous
Cullet Glass (Strawberry Glass)
Amorphous Silicon Dioxide (SiO2) with metallic dopants
Mineraloid (Synthetic/Man-made)
Goldstone (Synthetic Aventurescence Glass)
Cuprous Aventurescent Glass (Silicon Dioxide with Copper inclusions)
mineraloid / man-made material
Snowflake Obsidian
Obsidian with Cristobalite inclusions (Amorphous SiO2 + SiO2 inclusions)
igneous
Apache Tear (Obsidian)
Obsidian (Hydrated Amorphous Silica, SiO2 + MgO/Fe3O4)
igneous
Red Painted Rock
Artificial Coated Lithic Fragment
sedimentary
Flint
SiO2 (Cryptocrystalline Quartz)
sedimentary
Pumice
Pumice
igneous
Pebble
Lithified rock fragment / Sedimentary clast
sedimentary
Tumbled Rose Quartz
Quartz (Silicon Dioxide, SiO2 with trace amounts of titanium, iron, or manganese)
mineral
Mahogany Obsidian
Volcanic Glass (SiO2 with iron and magnesium oxides)
igneous
Red Coral
Corallium rubrum
gemstone
Fulgurite
Lechatelierite
mineral
Brachiopod Fossil in Sedimentary Rock
Phylum Brachiopoda fossil imprint in sedimentary matrix
fossil
Fulgurite
Lechatelierite (Fused Silica)
mineral
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Snowflake Obsidian
Volcanic Glass with Cristobalite Inclusions
igneous
Limonite
FeO(OH)•nH2O
mineral
Manganese Nodule
Polymetallic Nodule (Hydrous manganese and iron oxides)
mineral
Limonite / Goethite (Ironstone Nodule)
Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)
mineral
Pebble
Lithic fragment / Sedimentary clast
sedimentary
Fulgurite
Lechatelierite (Silica glass)
mineral
Moldavite
Tektite (Silica Glass - SiO2 + Al2O3, FeO, MgO, CaO, Na2O, K2O)
gemstone
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Tektite (Indochinite)
Tektite (Natural silica glass)
meteorite
Obsidian (Polished)
Obsidian (Volcanic glass, primarily SiO2)
igneous
Sea Glass
Silicon dioxide (mostly)
mineral
Pumice
Pumice (extrusive volcanic glass)
igneous
Anthracite Coal
Anthracite (Carbon-rich metamorphic coal)
sedimentary
Sandstone Concretion
Carbonate-cemented Sandstone Concretion
sedimentary
Anthracite Coal
Anthracite (Highly Metamorphosed Coal)
sedimentary
Obsidian Arrowhead
Obsidian (volcanic glass, SiO2 rich)
igneous
Ironstone Nodule
Ferruginous Sandstone / Limonite Concretion
sedimentary
Tektite
Tektite (meteoritic glass)
meteorite
Ironstone Concretion (Boxwork)
Siderite-Limonite Concretion (FeO(OH)·nH2O)
sedimentary
Mahogany Obsidian
Obsidian (Volcanic Glass with Hematite inclusions)
igneous