Borosilicate Glass (Manufactured)
SiO2 + B2O3 (Silicon dioxide and Boron trioxide)
Synthetic/Amorphous Solid
Category
Manufactured Glass
Browse manufactured glass specimens identified by the Rock Identifier community.
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Green glassy slag or manufactured glass bead
Noncrystalline silicate glass; likely industrial glass/slag, not a true mineral
mineral
Sea Glass
Amorphous silicon dioxide (glass)
mineral
Sea Glass
Silica (SiO2) - Amorphous
Mineral
Goldstone
N/A (Synthetic Glass with Copper Inclusions)
Manufactured Glass
Polished black stone, likely obsidian
Volcanic glass; primarily silica-rich, noncrystalline SiO₂
igneous
Tumbled pale quartz/chalcedony fragment
Quartz (SiO₂), possibly microcrystalline chalcedony
mineral
Black obsidian (probable)
Volcanic glass; primarily SiO₂-rich rhyolitic composition
igneous
Tumbled mahogany obsidian
Volcanic glass, predominantly rhyolitic silica (SiO₂), with iron-oxide inclusions
igneous
Sea Glass
Amorphous silicon dioxide (Man-made glass weathered by nature)
mineral
Obsidian (Blue)
Volcanic Glass (SiO2)
igneous
Green Sea Glass
Man-made vitreous material (silica glass)
gemstone
Likely polished black stone or obsidian
Obsidian (volcanic glass), chiefly SiO₂
igneous
Goldstone
Not a natural mineral or rock. It is an ornamental glass.
Manufactured Glass (Simulant)
Clear quartz pebble or glass-like quartz specimen
Quartz (silicon dioxide, SiO₂)
mineral
Leopard jasper (orbicular jasper)
Silicified volcanic rock, chiefly microcrystalline quartz/chalcedony (SiO₂) with feldspar and iron-oxide inclusions
metamorphic
Polished blue calcite sphere (tentative identification)
Calcite, CaCO₃; blue color generally results from trace impurities or inclusions
mineral
Likely obsidian (possibly tektite or slag glass)
Volcanic glass; primarily SiO₂, noncrystalline
igneous
Opalite
Synthetic Opalised Glass
mineraloid (synthetic)
Blue glass-like tumbled specimen
Most likely cobalt-blue slag glass or manufactured glass; not confidently identifiable as a natural mineral from the image
mineral
Polished black obsidian pyramid/block
Obsidian — natural volcanic glass, chiefly rhyolitic silica (approximately 70–75% SiO₂)
igneous
Quartz
Silicon Dioxide (SiO2)
mineral
Tumbled black stone, likely obsidian
Obsidian (natural volcanic glass; mainly silica-rich rhyolitic composition)
igneous
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Sandstone
Clastic Sedimentary Rock
sedimentary
Sandstone
Arenite (SiO2 primarily)
sedimentary
Feldspar (Plagioclase / Potassium Feldspar)
Feldspar Group (KAlSi3O8 - NaAlSi3O8 - CaAl2Si2O8)
mineral
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Sandstone
Clastic sedimentary rock (primarily quartz arenite)
sedimentary
Sandstone
Arenite (primarily Quartz, SiO2)
sedimentary
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone
Sedimentary rock composed mainly of sand-sized minerals or rock grains
sedimentary
Quartzite
Metamorphic Quartz Rock (SiO2)
metamorphic
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite (Clastic Sedimentary Rock)
sedimentary
Sandstone
Clastic sedimentary rock (quartz arenite)
sedimentary
Sandstone
Arenite (SiO2 primarily)
sedimentary
Quartz Crystal (Amethyst)
Silicon Dioxide (SiO2)
mineral
Quartzite
Metamorphic Quartzite
metamorphic