Chert (Jasper/Agate variety)
Cryptocrystalline Quartz (SiO2)
Category
Browse mineral (variety of chalcedony) specimens identified by the Rock Identifier community.
Chert (Jasper/Agate variety)
Cryptocrystalline Quartz (SiO2)
Blue Quartz (Aventurine)
Silicon Dioxide (SiO2) with fibrous inclusions (commonly Dumortierite)
Chert (Common Opal/Chalcedony)
Microcrystalline Quartz (SiO2)
Banded Jasper (possibly "Picture Jasper")
Jasper (a microcrystalline variety of Quartz / Silicon Dioxide - SiO2)
Chert or flint fragment
Microcrystalline quartz (SiO₂), often with chalcedony
Quartz (likely Milky Quartz or Chalcedony)
Quartz (SiO2 - Silicon Dioxide)
Pink Botswana Agate
Silicon Dioxide (SiO₂), a cryptocrystalline variety of Quartz and Chalcedony
Milky Quartz
Silicon Dioxide (SiO2)
Agate (Chalcedony)
Silicon Dioxide (SiO2)
Chalcedony (River Agate)
Silicon Dioxide (SiO2)
Chalcedony (Common Opal variant or Agate)
Silicon Dioxide (SiO2)
Jasper (Banded Jasper)
Silicon Dioxide (SiO2) with impurities
Chert / Flint
Silicon Dioxide (Microcrystalline Quartz, $SiO_2$)
Milky Quartz
Quartz (Silicon Dioxide - SiO2)
Tumbled pink calcite (probable)
Calcite, calcium carbonate (CaCO₃), likely manganocalcite variety
Chert (Chalcedony/Common Opal)
Microcrystalline Quartz (SiO2)
Blue Chalcedony
Silicon Dioxide (SiO2)
Yellow Chalcedony (Agate)
Silicon Dioxide (SiO2)
Yellow Agate
Silicon Dioxide (Chalcedony), SiO2
Red Jasper
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Botryoidal Chalcedony (Agate)
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Amethyst
Quartz variety; chemical formula: SiO₂ (silicon dioxide) with Fe³⁺ impurities
Polished yellow-orange chalcedony (likely carnelian)
Chalcedony, microcrystalline quartz (SiO₂), iron-colored variety commonly called carnelian
Chalcedony / Agate Nodule
Silicon Dioxide (SiO2)
Chalcedony on Ironstone
Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3/FeOOH)
Blue Lace Agate (Banded Chalcedony)
Silicon Dioxide (SiO₂)
Quartz
Quartz (SiO₂ - Silicon Dioxide)
Chalcedony (Agate)
Silicon Dioxide (SiO2)
Quartz (Chalcedony / Rough Quartz Pebble)
Silicon Dioxide (SiO2)
Jasper (likely river-tumbled)
Jasper (Silica/Silicon Dioxide, SiO2)
Bloodstone
Heliotrope (Chalcedony)
Chert (Chalcedony-rich sedimentary rock)
Cryptocrystalline Quartz (SiO2)
Dark gray chert or flint nodule
Microcrystalline quartz (SiO₂), commonly chalcedony/quartz
Pink quartz bead strand (likely rose quartz or pink dyed quartz)
Quartz, silicon dioxide (SiO₂); probable rose quartz variety, possibly dyed or treated quartz/chalcedony
Chert or flint
Microcrystalline quartz (SiO₂), likely chalcedony-rich chert
Chalcedony Geode / Agate Nodule
Cryptocrystalline Quartz (SiO2)
Chert (or Chalcedony)
Microcrystalline Quartz (SiO2)
Agate
Silicon Dioxide (Chalcedony), SiO2
Tumbled orange chalcedony (likely carnelian)
Carnelian, a cryptocrystalline variety of quartz (SiO₂)
Chert (Agatized/Chalcedony variety)
Microcrystalline Quartz (SiO2)
Chert (Agatized/Chalcedony variety)
Microcrystalline Quartz (SiO2)