Chert / Flint
Cryptocrystalline quartz (SiO2)
Category
Browse man made glass specimens identified by the Rock Identifier community.
Chert / Flint
Cryptocrystalline quartz (SiO2)
Chert (Arrowhead Fragment)
Microcrystalline Quartz (SiO2)
Tumbled purple quartz, likely amethyst or lavender quartz
Quartz (SiO₂), probably iron-colored amethyst; exact variety uncertain from the image
Quartzite
Metamorphic Quartzite (SiO2)
Chert
Microcrystalline Quartz (SiO2)
Sandstone
Arenite (SiO2 primarily)
Chert Nodule
Microcrystalline Quartz (SiO2)
Chert (Jasper)
Microcrystalline Quartz (SiO2)
Sea Glass (Frosted Glass)
Amorphous Silica (SiO2) with various metal oxide impurities
Sea Glass (Turquoise/Aqua)
Amorphous Silica (SiO2) with transition metal dopants
Banded Chert / Chalcedony
Silicon Dioxide (SiO2)
Black stone bead bracelet
Likely black tourmaline (schorl), though identification is uncertain from the image
Likely weathered granite or granitic gneiss fragment
Granite; primarily quartz, feldspar, and mica
Chert (often called Flint or Jasper)
Microcrystalline Quartz (SiO2)
Chert (often called Flint or Agate nodule)
Cryptocrystalline Quartz (SiO2)
Possible basalt or industrial iron-rich slag
Basalt (plagioclase–pyroxene rock); identification uncertain from image
Chert (Flint)
Chert (Cryptocrystalline Silica, SiO2)
Chert (Flint)
Chert (SiO2)
Chert (Nodule)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Quartzite
Quartzite (SiO2)
Chert (River Siltstone/Quartzite type)
Microcrystalline Quartz (SiO2)
Quartzite
Metamorphic Quartzite (SiO2)
Flint (or Chert with cortex)
Silicon dioxide (SiO2)
Smoky Quartz
Smoky Quartz (Silicon Dioxide - SiO2)
Amethyst (or Light Amethyst / Rose Quartz)
Quartz (Silicon Dioxide, SiO2)
Clear Quartz
Silicon Dioxide (SiO2)
Chert (varieties include Flint and Jasper)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Polished garnet bead bracelet
Garnet group, likely almandine–pyrope solid solution; commonly approximated as Fe₃Al₂(SiO₄)₃–Mg₃Al₂(SiO₄)₃
Cullet Glass (Industrial Slag Glass)
Amorphous Silica (SiO2) with metallic oxide impurities
Quartzite Pebble
Quartzite (SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Beaded blue-and-green gemstone jewelry
Likely dyed or treated chalcedony/agate and green aventurine or glass-like stone; exact identification requires testing
Chert
Microcrystalline quartz (SiO2)
Iron Slag
Ferrous slag (primarily silicates and oxides of calcium, iron, and magnesium)
Smoky Quartz Cluster
Smoky Quartz (Silicon Dioxide - SiO2)
Amethyst (with Pyrite and other minerals)
Silicon Dioxide (SiO2)
Mounted faceted gemstone ring
Likely diamond (carbon, C), though the image is insufficient for definitive identification
Blue gemstone bead bracelet, likely lapis lazuli or dyed stone
Uncertain from image; possible lazurite-bearing lapis lazuli (Na₃Ca(Si₃Al₃)O₁₂S) or dyed quartz/glass imitation
Amethyst
Silicon Dioxide (SiO2) with Fe3+ impurities
Chert (often called Flint)
Microcrystalline Quartz (SiO2)
River Pebbles (Chert and Quartzite)
Sedimentary Clastic Rock (Silica-rich)
Chert Pebble
Chert (Microcrystalline Quartz, SiO2)