Agate (Nodule/Chert)
Silicon Dioxide (SiO2)
sedimentary
Category
Synthetic Polymer (Synthetic Material)
Browse synthetic polymer (synthetic material) specimens identified by the Rock Identifier community.
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Sandstone
Sandstone (SiO2 predominant)
sedimentary
Orbicular jasper / brecciated jasper
Silica-rich microcrystalline quartz (chalcedony), commonly with iron oxides and altered volcanic fragments
metamorphic
Dzi Bead (Agate Bead)
Cryptocrystalline Quartz (SiO2) - Chalcedony/Agate
mineral
Petrified Wood
Silicified Wood (primarily SiO2)
fossil
Chert (Yellow Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood (Agatized/Silicified Wood)
Silicified Wood (SiO2)
sedimentary
Jade
Jadeite or Nephrite
Mineral/Mineraloid
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Travertine
Calcareous Tufa / Travertine (CaCO3)
sedimentary
Beach Quartzite Pebble
Quartzite (primarily SiO2)
metamorphic
Petrified Wood
Silicified Wood (SiO2)
mineral
Small rounded pebble, likely quartz-rich river stone
Indeterminate; likely quartz/chert-bearing lithic clast
sedimentary
Chert (Jasper)
Microcrystalline Quartz (SiO2) with Iron Oxide inclusions
sedimentary
Polished ocean jasper / brecciated jasper
Jasper, microcrystalline quartz (SiO₂), with iron-oxide and other silicate inclusions
mineral
Tumbled serpentine with dark magnetite/chromite matrix
Serpentinite; chiefly antigorite/lizardite, Mg3Si2O5(OH)4, with magnetite and possibly chromite
metamorphic
Polished green moss agate cabochon
Moss agate: microcrystalline quartz (SiO₂) with included chlorite/actinolite or iron-manganese minerals
mineral
Polished tree agate (likely)
Chalcedony (microcrystalline SiO₂) with green dendritic/inclusion minerals
mineral
Granite
Intrusive Igneous Rock
igneous
Chert (Flint)
Microcrystalline quartz (SiO2)
sedimentary
Weathered quartz-rich stone, possibly fossiliferous limestone
Indeterminate; likely calcite-rich limestone (CaCO₃) or weathered quartz-bearing rock
sedimentary
Diamond
Carbon (C)
gemstone
Granite
Felsic intrusive igneous rock
igneous
Chalcedony
Silicon Dioxide (SiO2)
sedimentary
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Basalt
Basalt (Mafic volcanic rock)
igneous
Chert (Flint Nodules)
Silicon Dioxide (SiO2)
sedimentary
Chert (or Cryptocrystalline Quartz)
Silicon Dioxide (SiO2)
sedimentary
Chert / Flint
Silicon Dioxide (SiO2)
sedimentary
Yellow Jasper
Silicon dioxide (SiO2) with iron oxide inclusions
mineral
Chalcedony
Silicon dioxide (SiO2)
mineral
Limestone Cobble
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Chert (varieties: Flint or Jasper)
Silicon dioxide (SiO2) / Microcrystalline Quartz
sedimentary
Granite Pebble
Granite (Felsic intrusive igneous rock)
igneous
Chert (River Stone)
Silicon Dioxide (SiO2)
sedimentary
Chert (River Pebble)
Cryptocrystalline Quartz (SiO2)
sedimentary
Slate
Low-grade Metamorphic Rock (composed of quartz, illite, chlorite)
metamorphic
Granite Pebble
Granite (Phaneritic Quartz-Feldspar Plutonic Rock)
igneous
Travertine (Tufa)
Chemical Limestone (CaCO3)
sedimentary
Chert (specifically Flint or Common Chert)
Silicon Dioxide (SiO2)
sedimentary
Coquina
Biogenic Limestone (Calcium Carbonate - CaCO3)
sedimentary