Flint
SiO2 (Cryptocrystalline Quartz)
sedimentary
Category
Man Made Glass
Browse man made glass specimens identified by the Rock Identifier community.
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Chert or Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Black Chert River Stone
Cryptocrystalline Quartz (SiO2)
sedimentary
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Sea Glass (Frosted Glass)
Amorphous Silica (SiO2) with various additives
Man-made material (Anthropogenic 'mineraloid')
Blue Goldstone
Aventurine Glass
Man-made mineral simulant (Glass)
Blue opalite (often sold as synthetic opal)
Opalite glass; amorphous hydrated silica if natural opal (SiO₂·nH₂O)
gemstone
Chert (Flint / Quartz Nodule)
Microcrystalline Quartz (SiO2)
sedimentary
Blue glassy mineral fragment, possibly sodalite or dyed/cobalt glass
Uncertain; likely sodalite (Na₈Al₆Si₆O₂₄Cl₂) if natural, but vivid blue color may indicate cobalt-colored glass
mineral
Pearl
Biogenic CaCO3 (Aragonite and Calcite)
mineral
Chert (varietal: Flint/Jasper)
Silicon Dioxide (SiO2)
sedimentary
Obsidian
Volcanic glass
igneous
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Goldstone (blue-goldstone–style glass) beads
Artificial aventurine glass, typically silica glass with copper inclusions; not a natural mineral
mineral
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Precious Coral (Red Coral)
Corallium rubrum (Calcium Carbonate, CaCO3)
mineral
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (70–75% SiO2)
igneous
Polished/tumbled brown-and-white mineral fragment
Indeterminate; possibly quartz-rich jasper, brecciated jasper, or an iron-stained quartz mineral
mineral
Quartzite
Metamorphic Rock (Mainly SiO2)
metamorphic
Obsidian (Black)
Obsidian (High-silica volcanic glass)
igneous
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide)
igneous
Sandstone
Arenite (SiO2, often with CaCO3 or Fe2O3 cement)
sedimentary
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Chert (Jasper variation)
Microcrystalline Quartz (SiO2)
sedimentary
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Chert Arrowhead
Chert (Cryptocrystalline variety of Quartz, SiO2)
sedimentary
Obsidian
Volcanic Glass (SiO2)
igneous
Chert (Yellow Jasper/Flint)
Silicon Dioxide (SiO2)
sedimentary
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Chert (Jasper/Flint variety)
Silicon Dioxide (SiO2)
sedimentary
Quartzite
Metamorphic Quartzite
metamorphic
Polished amethyst-bearing quartz
Quartz, SiO₂; purple coloration from irradiation and trace iron
mineral
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Green Quartzite
Metamorphic Quartz Sandstone (SiO2)
metamorphic
Red Jasper
Silicon Dioxide (SiO2) with Iron Oxide inclusions
sedimentary
Black-and-white agate geode pendant
Agate (microcrystalline quartz, SiO₂), likely a hollow geode slice with chalcedony and drusy quartz
mineral
Chert (often called Flint)
Chert (Cryptocrystalline Quartz, SiO2)
sedimentary
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Asphalt Pavement (with aggregate)
Asphalt concrete
man-made composite
Cardstock (Paper)
Cellulose (C6H10O5)n
sedimentary (man-made)