Obsidian
Obsidian (Volcanic Glass)
igneous
Category
Amorphous Solid
Browse amorphous solid specimens identified by the Rock Identifier community.
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Obsidian
Obsidian (Volcanic Glass, ~70% SiO2)
igneous
Chrysocolla
Hydrated copper silicate - Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O
mineral
Obsidian
Obsidian (Volcanic Glass, SiO2)
igneous
Goldstone
Avventurina (Cu + SiO2 glass)
mineral
Pumice
Vesicular volcanic glass
igneous
Pumice
Pumicite
igneous
Vesicular Basalt with Quartz/Chalcedony
Vesicular Basalt (primarily Plagioclase, Pyroxene, and Olivine with SiO2 infill)
igneous
Dendritic Opal
Hydrated Silica (SiO2·nH2O) with Manganese or Iron Oxide inclusions
mineral
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Igneous
Limonite (Iron Ore)
FeO(OH)·nH2O
mineral
Obsidian
Volcanic Glass (SiO2 + impurities)
igneous
Chrysocolla on Matrix
Hydrated copper phyllosilicate mineral (Cu,Al)2H2Si2O5(OH)4·nH2O
mineral
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
igneous
Limonite (also known as Yellow Ochre or Brown Hematite)
Limonite (Hydrated iron oxide-hydroxide, FeO(OH)·nH2O)
Mineral
Snowflake Obsidian
Vitreous volcanic silicate (SiO2 with Cristobalite inclusions)
Igneous
Ironstone Concretion (Limonite/Goethite)
Ferruginous Sandstone or Limonite (FeO(OH)·nH2O)
sedimentary
Shungite (or Black Onyx / Obsidian)
Amorphous Carbon (Shungite) / SiO2 (Onyx/Obsidian)
mineral
Obsidian
Obsidian (volcanic glass), predominantly amorphous SiO₂
Igneous
Tumbled amber
Fossilized tree resin; commonly succinite (organic resin, not a mineral)
fossil
Pumice
Pumice (Volcanic Glass)
igneous
Petrified Coral Fossil
Rugose or Tabulate Coral (Hexagonaria or similar fossilized cnidarian)
fossil
Pebble
Lithic fragment / Water-worn rock
sedimentary
Fossilized Dinosaur Bone
Perineralized Bone (Fluorapatite/Quartz replacement)
fossil
Amber
Fossilized Tree Resin
gemstone
Coal (Anthracite / Bituminous)
Organic Sedimentary Rock (Carbon-based)
sedimentary
Ironstone Concretion (Moqui Marble / Boji Stone)
Sedimentary Iron Oxide Concretion (Fe2O3 / FeO(OH))
sedimentary
Petrified Wood
Silicified wood / Permineralized wood (SiO2)
fossil
Fulgarite
Fulgurite (Lechatelierite / Vitrified Sand)
igneous
Hag Stone
Perforated sedimentary rock (typically limestone, sandstone, or flint)
sedimentary
Copper Ore (Malachite and Limonite bearing rock)
Copper-bearing rock with secondary copper minerals
mineral
Petrified Wood
Silicified Wood (SiO2)
fossil
Bauxite
Aluminum ore / Hydrated aluminum oxides
sedimentary
Pebble
Lithic fragment / Rounded rock fragment
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Obsidian
Volcanic glass
igneous
Melo Melo Pearl (or Golden Chalcedony / Yellow Jasper Sphere)
Non-nacreous calcium carbonate pearl (or SiO2 - Silicon Dioxide)
gemstone
Ironstone Nodules (Iron Concretion)
Siderite or Hematite Concretion
sedimentary
Moqui Marble (Shaman Stone)
Ironstone Concretion (Goethite/Hematite over Sandstone)
sedimentary
Chrysocolla in Matrix
Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O)
mineral
Common Opal (Potch)
Hydrated Silica (SiO2·nH2O)
mineral
Gossan (Limonite/Ironstone)
Hydrated Iron Oxide (FeO(OH)·nH2O)
sedimentary