Fossil Belemnite Guard
Belemnitella spp. (rostrum)
fossil
Category
Amorphous Solid
Browse amorphous solid specimens identified by the Rock Identifier community.
Learn about Amorphous Solid in the encyclopedia
View all →
Blue Lace Agate
Cryptocrystalline variety of Quartz (SiO2)
mineral
Porphyry
Porphyritic Igneous Rock (likely Porphyritic Andesite or Basalt)
igneous
Sodalite Syenite (popularly known as Yooperlite)
Sodalite-rich Syenite (composed of alkali feldspar and sodalite)
Igneous
Shale with Vein Infillings
Shale (a fine-grained clastic sedimentary rock). The veins could be Calcite (CaCO3), Quartz (SiO2), or other minerals.
Sedimentary Rock
Fossil gastropod shell
Calcareous mollusk shell, chiefly aragonite or calcite (likely a large marine gastropod)
fossil
Epidote (Greenstone)
Epidote (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH))
metamorphic
Green Aventurine
Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)2AlSi3O10(OH)2)
mineral
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Porphyritic Basalt (or Porphyry)
Porphyritic Basalt (Mafic volcanic rock with phenocrysts)
igneous
Agate Geode / Nodular Chalcedony
Silicon Dioxide (SiO2) with impurities
mineral
Quartzite
Quartzite (SiO2)
metamorphic
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Quartzite
Quartzite (SiO2 silicon dioxide)
metamorphic
Petrified Wood (Jet or Coalified Wood appearance)
Silicified wood (principally SiO2) or Carbonized Wood
sedimentary
Polished fossiliferous limestone
Bioclastic limestone, commonly called fossil limestone or marble-like limestone
sedimentary
Quartzite Pebble
Quartzite (SiO2)
metamorphic
Quartzite (Sugar Quartz)
Quartzite (primarily SiO2)
metamorphic
Quartzite Pebble
Metamorphic Quartz Sandstone (SiO2)
metamorphic
Quartzite (Beach Pebble)
Quartzite (Composition: SiO2)
metamorphic
Fine-grained brown sand or weathered soil
Unconsolidated siliciclastic sediment, likely quartz-rich sand (SiO₂) mixed with iron-oxide-coated grains
sedimentary
Yellow Agate (Chalcedony)
Silicon Dioxide (SiO2)
sedimentary
Chalcedony (Agate and Carnelian varieties)
Silicon Dioxide (SiO2)
mineral
Black Onyx
Chalcedony (Silicon Dioxide - SiO2)
mineral
Natural Freshwater Pearl
Calcium Carbonate (Aragonite and Calcite), CaCO3
gemstone
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Quartzite
Quartzite (Primary mineral: Quartz, SiO2)
metamorphic
Geode (Unopened Keokuk Geode)
Silicon Dioxide (SiO2) - Chalcedony / Quartz exterior
mineral
Polished pink chalcedony (likely pink agate/geode)
Microcrystalline quartz, SiO₂; chalcedony with iron-bearing inclusions and possible druzy quartz
mineral
Biotite on Quartz
Biotite Mica (K(Mg,Fe)3AlSi3O10(F,OH)2)
mineral
Blue Quartzite
Quartzite (primarily SiO2 with inclusions like Dumortierite or Magnesio-riebeckite)
metamorphic
Blue Agate (Dyed Chalcedony)
Silicon Dioxide (SiO2)
mineral
Bismuth Crystal
Bismuth (Bi)
mineral
Greenstone / Serpentinite
Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)3(Si, Al, Fe)2O5(OH)4
metamorphic
Botryoidal chalcedony (likely white quartz/chalcedony)
Microcrystalline quartz, SiO₂; possibly partly altered carbonate or opaline silica
mineral
Petrified Wood
Silicified Wood (SiO2)
fossil
Petrified Wood
Silicified Wood
fossil
Geode (Quartz / Chalcedony Geode)
Silicon Dioxide (SiO2) - Quartz / Chalcedony
sedimentary
Agate Geode
Silicon Dioxide (SiO2) - Chalcedony / Quartz Variety
Mineral
Geode (Quartz)
Silicon Dioxide (SiO2)
mineral
Dyed Crackle Quartz
Silicon Dioxide (SiO2) with synthetic dye
mineral
Fossiliferous limestone (likely stromatoporoid/coral limestone)
Calcite-rich carbonate rock, chiefly CaCO₃; visible fossil structures may be tabulate coral or stromatoporoid
fossil