Black obsidian (probable)
Volcanic glass; primarily SiO₂-rich rhyolitic composition
igneous
Category
Synthetic (Glass)
Browse synthetic (glass) specimens identified by the Rock Identifier community.
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Muscovite
Muscovite (KAl2(AlSi3O10)(OH)2)
mineral
Muscovite Mica
KAl2(AlSi3O10)(F,OH)2
mineral
Muscovite Mica (likely on Quartz/Feldspar)
Muscovite - KAl2(AlSi3O10)(OH)2
mineral
Muscovite Mica Schist
Muscovite Schist (KAl2(AlSi3O10)(OH)2)
metamorphic
Muscovite Schist
Mica Schist (primarily KAl2(AlSi3O10)(OH)2)
metamorphic
Muscovite Schist
Mica Schist (KAl2(AlSi3O10)(OH)2)
metamorphic
Milky Quartz with inclusions
Silicon Dioxide (SiO2)
mineral
Obsidian
Obsidian (Volcanic Glass)
igneous
Dark flint or chert fragment
Microcrystalline quartz (SiO₂), commonly called flint when dark and nodular
sedimentary
Muscovite Mica
KAl2(AlSi3O10)(F,OH)2
mineral
Pegmatite with Mica
Granitic Pegmatite (containing Muscovite and Biotite)
igneous
Muscovite Schist with Quartz
KAl2(AlSi3O10)(OH,F)2 (Muscovite) in Schist
metamorphic
Snowflake Obsidian
Spherulitic Obsidian (Amorphous Volcanic Glass with Cristobalite inclusions)
igneous
Chert (often called Flint or River Pebble)
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Green Aventurine
SiO2 (Silicon Dioxide with Fuchsite inclusions)
mineral
Muscovite Mica (with Quartz)
Muscovite (KAl2(AlSi3O10)(OH)2)
mineral
Muscovite Mica
KAl2(AlSi3O10)(F,OH)2
mineral
Obsidian
Obsidian (Volcanic glass, primarily SiO2)
igneous
Quartz with Muscovite Mica
SiO2 with KAl2(AlSi3O10)(OH)2
mineral group
Blue Goldstone
Man-made glass with suspended copper, cobalt, or manganese particles
man-made glass
Blue Sea Glass
Amorphous Silica (Anthropogenic glass)
not a rock (man-made origin)
Red Slag Glass
Amorphous Silica (Industrial byproduct with metallic oxide dopants)
Mineraloid / Industrial Byproduct
Slag
Ferrous slag (by-product of iron smelting)
Mineraloid / Anthropogenic
Muscovite Mica
Muscovite, KAl2(AlSi3O10)(OH)2
mineral
Chert (Quartz)
Silicon dioxide (SiO2)
sedimentary
Green Aventurine
Quartz containing Fuchsite (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)
mineral
Muscovite
Muscovite (KAl2(AlSi3O10)(OH)2)
mineral
Muscovite Mica (in Quartz/Feldspar Matrix)
Muscovite - KAl2(AlSi3O10)(OH)2
mineral
Muscovite
Muscovite (KAl2(AlSi3O10)(OH)2)
mineral
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(OH)2)
mineral
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(OH)2)
mineral
Chert (specifically Gray Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Mica (Muscovite)
Potassium aluminum silicate - KAl2(AlSi3O10)(OH)2
mineral
Likely tumbled or cut quartz/chalcedony fragment
Silicon dioxide (SiO₂), probably microcrystalline quartz or quartz
mineral
Pumice
Pumice
igneous
Libyan Desert Glass
Libyan Desert Glass (Tektite / Impact Glass)
meteorite
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
igneous
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Snowflake Obsidian
Volcanic Glass (SiO2 with Cristobalite inclusions)
igneous
Sea Glass (Kelly Green)
Amorphous Silica (Silicon Dioxide with Iron/Chromium additives)
Anthropogenic specimen (Man-made material)
Green Slag Glass
Amorphous Silica / Glassy Blast Furnace Slag
Mineraloid (Industrial byproduct)