Clear quartz fragment (rock crystal)
Quartz, silicon dioxide (SiO₂)
Category
Browse synthetic glass specimens identified by the Rock Identifier community.
Clear quartz fragment (rock crystal)
Quartz, silicon dioxide (SiO₂)
Cobalt Blue Glass / Cullet Glass
Silicon dioxide (Amorphous man-made glass)
Chert (Iron-stained)
Microcrystalline Silica (SiO2)
Cullet Glass (sometimes mistaken for Blue Obsidian or Slag)
Amorphous Silicon Dioxide (SiO2) with chemical additives (e.g., Cobalt for blue color)
Green glassy mineral specimen, likely chromium-bearing fluorite (tentative)
Fluorite, CaF₂, possibly green fluorite; identification uncertain from image
Blue slag glass or dyed glass-like industrial material
Amorphous silicate glass; likely copper-bearing blue slag, but possibly colored man-made glass
Cullet (Slag Glass)
Amorphous Silica (Industrial byproduct)
Tumbled mahogany obsidian
Volcanic glass, predominantly rhyolitic silica (SiO₂), with iron-oxide inclusions
Tumbled amber-brown quartz (probable smoky quartz or carnelian)
Quartz, SiO₂; color may reflect iron impurities or irradiation
Sea Glass (White/Clear)
Amorphous Silica (Alkali-Lime-Silica Glass), SiO2 + Na2O + CaO
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(OH)2)
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(OH)2)
Muscovite Mica
Muscovite: KAl2(AlSi3O10)(OH)2
Sea Glass
Amorphous Silica (Glass) SiO2
Slag Glass (Cullet Glass)
Amorphous Silica (Industrial byproduct)
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(F,OH)2)
Polymer Clay (Mock Mineral)
Polyvinyl chloride (PVC) with plasticizers and pigment
Gastly (Trick or Trade Halloween Series)
Cellulose-carbonaceous composite (Lignocellulose laminated with pigmentary polymers)
Hand-Drawn Trading Card (Amateur Artwork)
Cellulose-based substrate with wax/graphite/ink deposit (n/a for minerals)
Libyan Desert Glass
Impact-melt silica glass (SiO2 + traces of Al, Fe, Ti)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Green sea glass (likely bottle glass)
Human-processed soda–lime silicate glass; not a natural mineral or rock
Quartz with Mica (Pegmatite)
Silicon Dioxide (SiO2) with Potassium Aluminum Silicate Hydroxide (KAl2(AlSi3O10)(OH,F)2)
Snowflake Obsidian
Hydrated Volcanic Glass with Cristobalite inclusions
Quartz with Muscovite Mica
Silicon Dioxide (SiO2) with Potassium Aluminum Silicate Hydroxide (KAl2(AlSi3O10)(OH)2)
Muscovite Mica (with Schist)
Muscovite - KAl2(AlSi3O10)(OH)2
Muscovite Mica
Muscovite - KAl2(AlSi3O10)(OH)2
Cullet Glass (Man-made Glass Slag)
Amorphous Silica (SiO2) with chemical additives
Possible tumbled obsidian
Volcanic glass, primarily rhyolitic silica glass (SiO₂-rich)
Glass Nugget (Tumbled Glass)
Amorphous Silicon Dioxide (SiO2) with additives
Snowflake Obsidian
Obsidian with Cristobalite inclusions
Blue Slag Glass
Man-made Silicon Dioxide (Amorphous)
Green Slag
Anthropogenic Silicate Glass
Cobalt Blue Slag Glass
Amorphous Silicon Dioxide (anthropogenic) with Cobalt additives
Black glassy fragment, likely obsidian or industrial glass
Volcanic glass (obsidian), chiefly amorphous SiO₂; identification uncertain from image
Snowflake Obsidian
Spherulitic Obsidian (Volcanic Glass with Cristobalite)
Green Quartz / Chrysoprase / Sea Glass
Silicon Dioxide (SiO2)
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(OH)2)
Mica (Muscovite)
Muscovite (KAl2(AlSi3O10)(OH)2)
Muscovite Mica in Quartz Matrix
Muscovite (KAl2(AlSi3O10)(OH)2) in Quartz (SiO2)
Goldstone and pink quartz bead strands
Goldstone is aventurescent copper-bearing glass; pink beads are likely rose quartz (SiO₂), though dyed or glass imitations are possible
Snowflake Obsidian
Volcanic Glass with Cristobalite inclusions