Obsidian
Obsidian (Volcanic Glass) SiO2 (70% or more)
igneous
Category
Glass
Browse glass specimens identified by the Rock Identifier community.
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Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
igneous
White Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
mineral
Quartz (Sea Glass or River-worn Pebble style)
Silicon Dioxide (SiO2)
mineral
Sapphire (Blue)
Corundum (Al2O3)
mineral
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite (SiO2 + Fe2O3)
igneous
Obsidian
Amorphous volcanic glass (primarily SiO2)
igneous
Pumice
Vesicular volcanic glass (Amorphous silica mixed with various oxides)
igneous
Terrazzo (with Marble and Granite fragments)
Cementitious or resinous composite containing Calcium Carbonate (CaCO3) and Silicates
sedimentary (man-made composite)
Pumice
Pumice (a highly vesicular extrusive igneous rock)
igneous
Mahogany Obsidian
Volcanic Glass (predominantly SiO2 with Fe2O3 inclusions)
igneous
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz (Gravel Pebble)
Silicon Dioxide (SiO2)
mineral
Quartz (Small Fragment)
Silicon Dioxide (SiO2)
mineral
Quartz in Matrix
Silicon Dioxide (SiO2)
mineral
Apache Tears (Tumbled Obsidian)
Volcanic Glass (SiO2 + impurities)
igneous
Pumice
Pumice (a vesicular volcanic glass)
igneous
Snowflake Obsidian
Volcanic glass (SiO2) with Cristobalite (SiO2) inclusions
igneous
Obsidian (in jewelry setting)
Volcanic Glass (Amorphous Silica)
igneous
Obsidian
Volcanic glass (SiO2 + impurities)
igneous
Cat's Eye Moonstone (Simulated/Synthetic or natural Cat's Eye Quartz/Glass)
There is no single scientific name. The appearance suggests either: Moonstone (feldspar group), Cat's Eye Quartz (SiO2), Apatite (Ca5(PO4)3(F,Cl,OH)), or most likely a synthetic material such as Fiber Optic Glass or 'Opalite' (a type of glass).
Mineral
Tektite (Indochinite)
Tektite (High-silica natural glass)
mineralogical glass/meteorite impactite
Snowflake Obsidian (Tumbled)
Obsidian with Cristobalite inclusions
igneous
Green Aventurine
Aventurine Quartz (SiO2 with Fuchsite inclusions)
metamorphic
Mica (Muscovite) in Granite
Muscovite (KAl2(AlSi3O10)(OH)2)
mineral
Green Aventurine
Aventurine Quartz (SiO2 + Fuchsite inclusions)
mineral
Aventurine (Green Quartz)
Silicon dioxide with inclusions (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)
mineral
Quartzite river stone
Quartzite (SiO2)
metamorphic
Quartzite
Quartzite (SiO2)
metamorphic
Chert
Microcrystalline or cryptocrystalline quartz (SiO2)
sedimentary
Chert (Flint)
Chert (SiO2)
sedimentary
Quartzite cobblestone
Quartzite (primarily SiO2)
metamorphic
Quartzite
Quartzite (primarily SiO2)
metamorphic
Aventurine
Silicon Dioxide (SiO2 with inclusions of Fuchsite mica)
mineral
Quartzite pebble
Quartzite (SiO2)
metamorphic
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite inclusions (SiO2 + Fe2O3)
igneous