Sea Glass
Amorphous silicon dioxide (glass)
mineral
Category
Synthetic Glass
Browse synthetic glass specimens identified by the Rock Identifier community.
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Milky quartz-bearing rock, possibly quartzite
Quartz (SiO₂), likely in a quartzite or quartz-rich metamorphic matrix
metamorphic
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(F,OH)2)
mineral
Green Aventurine
Silicon Dioxide (SiO2) with inclusions of Fuchsite
metamorphic
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(F,OH)2)
mineral
Aventurine
Silicon Dioxide (SiO2) with inclusions of Fuchsite
mineral
Slag Glass
Amorphous Silica / Glass Slag
industrial byproduct (anthropogenic rock-like material)
Obsidian
Volcanic Glass
igneous
Obsidian
Volcanic Glass
igneous
Obsidian
Volcanic Glass
igneous
Obsidian
Volcanic Glass
igneous
Obsidian
Volcanic Glass
igneous
Obsidian
Volcanic glass
igneous
Obsidian
Volcanic glass
igneous
Milky Quartz with inclusions
Silicon Dioxide (SiO2)
mineral
Tektite (Indochinite)
Natural glass (High-silica impact glass)
mineral
Obsidian
Volcanic Glass (Amorphous SiO2-rich glass)
Igneous
Cullet Glass (Slag Glass)
Amorphous Silicon Dioxide (Industrial Man-made)
mineraloid
Green Aventurine
Aventurine Quartz (SiO2 + Fuchsite mica)
Mineral
Possible industrial slag or basaltic volcanic glass
Likely iron-rich vitreous slag; natural alternative: basaltic glass (tachylite)
igneous
Tumbled black stone, likely black obsidian
Obsidian (volcanic glass; chiefly silica-rich rhyolitic composition)
igneous
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(OH)2)
mineral
Muscovite Schist with Quartz
Muscovite (KAl2(AlSi3O10)(OH)2) in Quartz Matrix
metamorphic
Mica Specimen (Schist / Muscovite)
Muscovite / Biotite Mica (KAl2(AlSi3O10)(F,OH)2)
metamorphic
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(OH)2)
mineral
Obsidian
Obsidian (Volcanic Glass)
igneous
Moldavite
Tektite
meteorite
Likely quartz or quartz-rich pebble
Quartz (SiO₂), possibly milky quartz or a small quartzite fragment
mineral
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
igneous
Pumice
Pumice
igneous
Blue Goldstone
Man-made glass with suspended copper, cobalt, or manganese particles
man-made glass
Likely polished quartz or glass-like mineral cabochon
Probably quartz (SiO₂), though the image cannot exclude man-made glass
mineral
Obsidian-like volcanic rock (likely basaltic volcanic glass)
Basaltic obsidian or tachylite; composition chiefly volcanic glass with plagioclase and pyroxene
igneous
Red Slag Glass
Amorphous Silica (Industrial byproduct with metallic oxide dopants)
Mineraloid / Industrial Byproduct
Libyan Desert Glass
Libyan Desert Glass (Impactite / High-silica Lechatelierite)
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)
Black onyx or black obsidian bead bracelet
Likely black chalcedony (microcrystalline quartz, SiO₂); possibly volcanic glass (obsidian, SiO₂)
gemstone
Muscovite Mica
KAl2(AlSi3O10)(F,OH)2
mineral
Muscovite
Muscovite (KAl2(AlSi3O10)(OH)2)
mineral
Black obsidian (probable)
Volcanic glass; primarily SiO₂-rich rhyolitic composition
igneous