Basalt
Basalt (composition of plagioclase feldspar and pyroxene)
Category
Browse industrial byproduct (anthropogenic rock) specimens identified by the Rock Identifier community.
Basalt
Basalt (composition of plagioclase feldspar and pyroxene)
Basalt with Plagioclase Microphenocrysts
Amygdaloidal or Porphyritic Basalt
Granite
Phaneritic plutonic felsic rock (primarily Quartz, Feldspar, and Mica)
Lapis Lazuli
Na8[Al6Si6O24]Sn (Lazurite-rich metamorphic rock)
Basalt
Basalt (primarily composed of Plagioclase Feldspar and Pyroxene)
Lake Superior Agate
Cryptocrystalline Quartz (SiO2)
Dalmation Stone (often called Dalmatian Jasper)
Peralkaline Rock (Microgranite/Aplite), SiO2 with inclusions of Arfvedsonite
Basalt
Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)
Unakite
Epidotized Granite
Granite
Granite (compositionally of Quartz, Alkali Feldspar, and Plagioclase)
Vesicular Basalt (Lava Rock)
Scoriaceous Basalt
Quartz with Mica/Host Rock
Silicon Dioxide (SiO2) with Phyllosilicates
Clear Quartz / Rock Crystal
Silicon Dioxide (SiO2)
Basalt (River Rock Cobble)
Extrusive mafic volcanic rock (Basalt)
Granite
Granite (Felsic Plutonic Rock)
Granite
Granite (Felsic Plutonic Rock)
Chert (Nodule)
Chert (variety of microcrystalline quartz, SiO2)
Sandstone Concretion
Septarian Concretion (Nodule)
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic volcanic rock)
Chert (Jasper/Agate mix)
Microcrystalline Quartz (SiO2)
Wonderstone Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Herkimer Diamond
Quartz (Silicon Dioxide, SiO2)
Basalt with Olivine (Peridot)
Basalt containing (Mg,Fe)2SiO4
Petrified Wood
Silicified Wood (SiO2)
Amethyst Geodes
Silicon Dioxide (Quartz with Iron impurities), SiO2
Amethyst (Chevron Amethyst)
Amethystine Quartz (SiO2)
Pyrite in Shale
Iron Sulfide (FeS2) in Sedimentary Matrix
Petrified Wood
Silicified Wood (SiO2)
Chert (variations include Flint or Jasper)
Cryptocrystalline Quartz (SiO2)
Sandstone (Ferruginous Concretion)
Ferruginous Sandstone Concretion / SiO2 with Fe2O3 cement
Schist
Schist (Crystalline metamorphic rock)
Quartz Vein in Pelite (Metamorphic Rock)
Hydrothermal Quartz Veining in Metasedimentary Rock (SiO2)
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Granatic Pegmatite
Pegmatitic Granite
Copper-bearing Quartz (likely Chrysocolla or Malachite staining)
Cuprite, Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O) or Malachite staining on Quartz/Host Rock
Jasper
Silicon dioxide (SiO2)
Chert (specifically Gray Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Coquina
Bioclastic Limestone
Quartz / Common Opal
Silicon Dioxide (SiO2)
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
Chert / Flint
Chert (Microcrystalline Quartz, SiO2)
Chert (Jasper variety)
Silicon Dioxide (SiO2)