Petrified Wood
Silicified wood (primarily Silicon Dioxide, SiO2)
Category
Browse organic gemstone (often associated with sedimentary sequences) specimens identified by the Rock Identifier community.
Petrified Wood
Silicified wood (primarily Silicon Dioxide, SiO2)
Prehnite
Prehnite (Ca2Al2Si3O10(OH)2)
Yellow Chalcedony
Silicon Dioxide (SiO2)
Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3 with Carotenoid pigments)
Banded Chert (Ironstone/Jasper)
Cryptocrystalline Quartz (SiO2) with Iron Oxides
Chert with Iron Staining
Microcrystalline quartz (SiO2) with iron oxide inclusions
Petrified Wood
Silicified wood / Xylopal
Petrified Wood
Silicified wood (SiO2)
Jasper
Silicon Dioxide (SiO2) with impurities
Chert (specifically Flint or Jasper variant)
Microcrystalline Quartz (SiO2)
Chert / Flint
Silicon dioxide (SiO2)
Chert (variations include Flint)
Sedimentary cryptocrystalline quartz (SiO2)
Fossilized Shell Fragment
Invertebrate marine fossil, likely calcium carbonate replacement
Chert (Flint)
Chert (SiO2)
Chert (often called Flint)
Chert (Cryptocrystalline Silica, SiO2)
Chert
Microcrystalline Quartz (SiO2)
Chert (Yellow Jasper/Flint)
Silicon Dioxide (SiO2)
Chert (Black Chert / Flint)
Silicon Dioxide (SiO2)
Tahitian black pearl strand
Cultured pearl; aragonite (CaCO₃) nacre
Green Chert (Jasper)
Silicon Dioxide (SiO2)
Dragon Stone (Dragon Blood Jasper)
Epidote with Pietersite or Red Jasper inclusions (varied SiO2 and Ca2(Al,Fe)3(SiO4)3(OH))
Chert (Flint)
Microcrystalline Opaline Silica (SiO2)
Quartz (Peach/Orange variety)
Silicon Dioxide (SiO2)
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
Yellow Topaz
Aluminum silicate fluoride hydroxide, Al2SiO4(F,OH)2
Red Jasper (Tumbled)
Silicon Dioxide (SiO2) with iron oxide inclusions
Chert (Jasper variation)
Silicon dioxide (SiO2)
Chert (Nodular)
Microcrystalline Silica (SiO2)
Chert (Flint)
Cryptocrystalline Quartz (SiO2)
Lepidolite
K(Li,Al)3(Si,Al)4O10(F,OH)2
Morganite
Beryllium Aluminum Silicate, Be3Al2(SiO3)6
Malachite
Copper Carbonate Hydroxide, Cu2CO3(OH)2
Chert (with Quartz Druzy)
Microcrystalline Silica (SiO2)
Rounded brown chert or flint pebble
Microcrystalline quartz (chalcedony), SiO₂
Pink Opal
Amorphous Hydrous Silica (SiO2·nH2O)
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Possible garnet crystal
Likely almandine garnet, Fe₃Al₂(SiO₄)₃; identification is uncertain from this small image
Chert (varieties include Flint and Jasper)
Silicon Dioxide (SiO2) / Microcrystalline Quartz
Yellow Jasper
Cryptocrystalline Quartz (SiO2 with Iron inclusion)
Peridotite / Olivine-rich Xenolith
Ultramafic igneous rock (predominantly olivine and pyroxene)
Chert (Flint)
Silicon Dioxide (SiO2)
Banded Chert (Jasper)
Silicon Dioxide (SiO2)