Petrified Wood (Jet or Coalified Wood appearance)
Silicified wood (principally SiO2) or Carbonized Wood
Category
Browse man made material (metal) specimens identified by the Rock Identifier community.
Petrified Wood (Jet or Coalified Wood appearance)
Silicified wood (principally SiO2) or Carbonized Wood
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, formula SiO2)
Rough amethyst-bearing quartz specimens
Quartz, SiO₂; purple coloration from trace iron and irradiation
Green Banded Chert (Agate/Jasper)
Silicon Dioxide (SiO2) with trace impurities of Chlorite or Glauconite
Rhyolitic Tuff
Rhyolitic Tuff / Pyroclastic rock
Polished green-and-white stone, likely serpentine or nephrite jade
Serpentine-group minerals, commonly antigorite/lizardite; possible nephrite (interlocking actinolite–tremolite)
Gravel / Crushed Stone
Aggregate (mixed mineral rock fragments)
Limestone
Calcite (CaCO3)
Vesicular volcanic rock, likely scoria
Scoria; composition commonly basaltic to andesitic, rich in plagioclase and pyroxene
Quartzite
Quartzite (SiO2)
Chalcanthite (Likely Synthetic/Lab-Grown)
Hydrated copper(II) sulfate (CuSO4·5H2O)
Dyed Quartz (often sold as 'Blue Quartz' or 'Blue Agate')
Silicon Dioxide (SiO2) with artificial pigment
Likely tumbled jasper or iron-stained quartzite
Microcrystalline quartz (SiO₂), possibly quartzite with iron-oxide inclusions
Tumbled blue-gray mineral specimen
Indeterminate; possibly dumortierite quartz, sodalite, or dyed stone
Polished Mexican “Crazy Lace” agate tower
Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide inclusions
Likely basalt pebble
Basalt; fine-grained mafic volcanic rock, chiefly plagioclase and pyroxene with possible olivine
Pink Quartzite
Quartzite (principally Silicon Dioxide, SiO2)
Laterite (Iron-rich bauxite or Gossan)
Ferricrete (Fe2O3·nH2O)
Chert (Jasper/Flint variant)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert / Flint
Microcrystalline quartz (SiO2)
Tanzanite
Blue-violet Zoisite (Ca2Al3(SiO4)3(OH))
Brecciated jasper/chert
Microcrystalline quartz (SiO₂), with iron-oxide and clay inclusions
Petrified Wood
Silicified Wood (SiO2)
Quartz
Silicon Dioxide (SiO2)
Sandstone
Arenite (Clastic Sedimentary Rock)
Sandstone
Arenite (primarily Quartz, SiO2)
Diamond
Carbon (C)
Vesicular volcanic rock, likely weathered scoria
Scoria (vesicular basaltic-andesitic volcanic rock), composition approximately plagioclase, pyroxene, and volcanic glass
Red Sandstone
Arenite (SiO2 with Fe2O3)
Sandstone
Arenite (composed primarily of SiO2)
Limestone
Calcium Carbonate (CaCO3)
Chert (or Flint)
Microcrystalline Quartz (SiO2)
Quartzite
Quartzite (primarily SiO2)
Limestone
Limestone (Calcium Carbonate, CaCO3)
Fossilized Bone Fragment
Petrified Osseous Material
Petrified Wood
Silicified Wood (primarily SiO2)
Chert
Microcrystalline Quartz (SiO2)
Tumbled brown pebble
Indeterminate; likely quartz-rich sandstone or chert
Petrified wood
Silicified wood, chiefly microcrystalline quartz (SiO₂)
Banded gneiss pebble
Biotite–quartz–feldspar gneiss (composition variable)
Tumbled jasper or rhyolitic porphyry
Silicic volcanic rock, likely rhyolite (quartz- and feldspar-rich), possibly jasperized
Serpentine
Serpentine group ((Mg,Fe,Ni,Al,Zn,Mn)3(Si,Al)2O5(OH)4)