Limestone
Calcium Carbonate (CaCO3)
sedimentary
Category
Synthetic Polymer (Synthetic Material)
Browse synthetic polymer (synthetic material) specimens identified by the Rock Identifier community.
Learn about Synthetic Polymer (Synthetic Material) in the encyclopedia
View all →
Chert (or Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Quartzite
Quartzite (primarily SiO2)
metamorphic
Limestone
Limestone (Calcium Carbonate, CaCO3)
Sedimentary
Green Glass Cullet / Recycled Glass
Amorphous Silicon Dioxide (SiO2) with various metal oxides
Man-made Glass (Not a natural rock or mineral)
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Carnelian/chalcedony rough
Microcrystalline quartz (SiO₂), iron-oxide-colored chalcedony
mineral
Fossilized Bone Fragment
Petrified Osseous Material
fossil
Slag (Industrial Glass/Glassy Rock)
Anthropogenic Vitreous Material
igneous
Tumbled yellow quartz (likely citrine or iron-stained quartz)
Quartz, SiO₂; yellow color from trace iron or irradiation/heat-related coloration
mineral
Petrified wood
Silicified wood, chiefly microcrystalline quartz (SiO₂)
fossil
Banded gneiss pebble
Biotite–quartz–feldspar gneiss (composition variable)
metamorphic
Tumbled jasper or rhyolitic porphyry
Silicic volcanic rock, likely rhyolite (quartz- and feldspar-rich), possibly jasperized
igneous
Serpentine
Serpentine group ((Mg,Fe,Ni,Al,Zn,Mn)3(Si,Al)2O5(OH)4)
metamorphic
Mudstone
Argillite / Siliciclastic sedimentary rock
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone (Tumbled/River Pebble)
Arenite (composed primarily of SiO2)
sedimentary
Quartz / Quartzite
Silicon Dioxide (SiO2)
Mineral / Metamorphic
Limestone
Calcite (CaCO3)
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone (Ferruginous)
Arenite with Iron Oxide matrix
sedimentary
Petrified Wood
Petrified Wood (Silicified Wood)
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Jasper
Silicon Dioxide (SiO2)
mineral
Chert Pebble
Microcrystalline Quartz (SiO2)
sedimentary
Mudstone
Lutylite (group of fine-grained sedimentary rocks)
sedimentary
Polished tiger’s-eye cabochon (probable)
Quartz variety, SiO₂, with fibrous riebeckite/crocidolite-derived inclusions
metamorphic
Quartzite
Quartz-rich metamorphic rock; chiefly SiO₂
metamorphic
Biotite schist (likely graphite-bearing)
Mica schist; chiefly quartz + biotite mica, with possible graphite and feldspar
metamorphic
Limestone
Sedimentary rock composed mainly of calcium carbonate (CaCO3)
sedimentary
Coquina / Limonite-stained Limestone
Sedimentary Limestone with Iron Oxyhydroxide (FeO(OH)·nH2O)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Petrified Wood
Silicified wood (Quartz/Chalcedony replacement of cellulose)
fossil
Petrified Wood
Silicified Wood (SiO2 as Quartz/Chert/Chalcedony)
sedimentary
Likely weathered quartz-rich stone or fossil fragment
Indeterminate; possibly quartz-bearing sandstone, iron-stained quartz, or a fragmentary fossil
mineral
Granite
Granite
Igneous
Banded iron formation fragment (likely hematite–magnetite ironstone)
Banded iron formation; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and microcrystalline quartz (SiO₂)
sedimentary
Weathered iron-rich rock, likely laterite or ironstone
Ferruginous laterite/ironstone, composed mainly of goethite (FeO(OH)), hematite (Fe₂O₃), and clay minerals
sedimentary
Rounded iron-stained quartzite or sandstone pebble
Quartzite, predominantly SiO₂, with iron-oxide staining
metamorphic
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Siltstone
Siltstone (composed of clastic quartz and feldspar grains)
sedimentary
Siltstone
Siltstone (composed of microscopic quartz and clay minerals)
sedimentary