Rounded brown chert or flint pebble
Microcrystalline quartz (chalcedony), SiO₂
Category
Browse organic gemstone (often associated with sedimentary sequences) specimens identified by the Rock Identifier community.
Rounded brown chert or flint pebble
Microcrystalline quartz (chalcedony), SiO₂
Petrified Wood
Silicified wood (primarily quartz replacing organic cellulose)
Banded Chert (Ironstone/Jasper)
Cryptocrystalline Quartz (SiO2) with Iron Oxides
Chert (often called Jasper or Flint)
Microcrystalline Silica (SiO2)
Petrified Wood
Silicified wood (SiO2)
Chert (Jasper variation)
Silicon dioxide (SiO2)
Jasper
Silicon Dioxide (SiO2) with impurities
Tahitian black pearl strand
Cultured pearl; aragonite (CaCO₃) nacre
Chert (specifically Flint or Jasper variant)
Microcrystalline Quartz (SiO2)
Chert (Yellow Jasper/Flint)
Silicon Dioxide (SiO2)
Chert
Microcrystalline quartz (SiO2)
Chert / Flint
Silicon dioxide (SiO2)
Yellow Jasper
Cryptocrystalline Quartz (SiO2 with Iron inclusion)
Pink Opal
Amorphous Hydrous Silica (SiO2·nH2O)
Chert
Microcrystalline Quartz (SiO2)
Chert (Black Chert / Flint)
Silicon Dioxide (SiO2)
Green Chert (Jasper)
Silicon Dioxide (SiO2)
Chert (Flint)
Chert (SiO2)
Chert (often called Flint)
Chert (Cryptocrystalline Silica, SiO2)
Rhodonite with Manganese Oxides
Rhodonite (Mn,Fe,Mg,Ca)SiO3
Chert (Flint)
Microcrystalline Opaline Silica (SiO2)
Chert (variations include Flint)
Sedimentary cryptocrystalline quartz (SiO2)
Fossilized Shell Fragment
Invertebrate marine fossil, likely calcium carbonate replacement
Red Jasper
Silicon dioxide (SiO2) with hematite impurities
Amber
Succinate (Fossilized Tree Resin)
Yellow Jasper
Silicon Dioxide (SiO2) with iron hydroxides (Goethite/Limonite)
Banded Chert (Jasper)
Silicon Dioxide (SiO2)
Red Jasper (Chert)
Silicon Dioxide (SiO2) with iron oxide inclusions
Jasper
Silicon dioxide (SiO2)
Chert (Nodular)
Microcrystalline Silica (SiO2)
Turquoise (possible Dyed Magnesite/Howlite)
CuAl6(PO4)4(OH)8·4H2O
Chert (Flint)
Cryptocrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (with Quartz Druzy)
Microcrystalline Silica (SiO2)
Chert (varieties include Flint and Jasper)
Silicon Dioxide (SiO2) / Microcrystalline Quartz
Quartz (Chert/Quartzite variant)
Silicon Dioxide (SiO2)
Jasper (Yellow/Brown variety)
Silicon Dioxide (SiO2) with iron oxide impurities
Amber
Succinicum (C10H16O)
Peridotite / Olivine-rich Xenolith
Ultramafic igneous rock (predominantly olivine and pyroxene)
Red Jasper
Silicon Dioxide (SiO2) with Hematite impurities
Chert (Jasper)
Microcrystalline Quartz (SiO2)
Red Chert (Jasper)
Cryptocrystalline Quartz (SiO2) with iron oxide inclusions