Limestone (specifically Iron-stained or Argillaceous Limestone)
Calcium Carbonate (CaCO3) with Iron Oxide (Fe2O3) impurities
sedimentary
Category
Industrial Byproduct (Often Confused With Igneous Rocks Or Meteorites)
Browse industrial byproduct (often confused with igneous rocks or meteorites) specimens identified by the Rock Identifier community.
Amethyst
Silicon Dioxide (SiO2) with iron impurities
mineral
Agate
Agate (Silicon Dioxide - SiO2)
mineral
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
mineral
Jasper (Red Jasper)
Silicon Dioxide (SiO₂)
sedimentary
Schorl (Black Tourmaline)
NaFe3Al6(BO3)3Si6O18(OH)4 (Sodium Iron Aluminum Borosilicate)
mineral
Basalt (Vesicular)
Extrusive mafic igneous rock
igneous
Almandine Garnet in Schist Matrix
Almandine - Fe3Al2(SiO4)3
metamorphic
Ferruginous Quartz
Silicon Dioxide (SiO2) with Hematite/Limonite impurities
mineral
Blue Calcite
Calcium Carbonate (CaCO3)
mineral
Basalt (Polished River Stone)
Mafic Volcanic Rock (primarily Plagioclase and Pyroxene)
Igneous
Amethyst
Silicon Dioxide (SiO2) with trace Iron (Fe3+)
mineral
Anthracite Coal
Anthracite
metamorphic
Vesicular Basalt (or Scoria)
Vesicular Basalt
igneous
Basalt
Basalt (Mafic volcanic rock)
Igneous
Glauconite (Sandstone or Shale)
Glauconite (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2
sedimentary
Opalite (Man-made Glass)
Synthetic Silicon Dioxide Glass (SiO2 + metal oxides)
Synthetic Mineral Simulant / Glass
Dalmatian Jasper
Peralkaline rhyolite with Arfvedsonite inclusions
igneous
Chert (Jasper/Flint variant)
Silicon Dioxide (SiO2)
sedimentary
Muscovite Mica
KAl2(AlSi3O10)(F,OH)2
mineral
Rose Quartz
Silicon dioxide (SiO2) with trace impurities of titanium, iron, or manganese
mineral
Vesicular Basalt (Amygdaloidal)
Vesicular Basalt (Fe-Mg rich extrusive volcanic rock)
igneous
Opalite
Synthetic Glass (Hydrated Crystalline Silicon Dioxide simulation)
mineral
Beach Pebble (likely Quartz or Chalcedony)
Silicon Dioxide (SiO2)
Mineral
Basalt Porphyry
Porphyritic Basalt
igneous
Porphyry
Porphyritic Rock
igneous
Diorite (Polished River Pebble)
Diorite (Intermediate intrusive igneous rock)
igneous
Cubic Zirconia (Simulated Diamond)
Zirconium Dioxide (ZrO2)
mineral (synthetic)
Zoisite with Ruby (Anyolite)
Zoisite – Ca2Al3(SiO4)3(OH) with inclusions of Ruby (Al2O3:Cr)
metamorphic
Bloodstone
Heliotrope (a variety of Cryptocrystalline Quartz / Jasper, SiO2)
mineral
Diorite
Diorite
igneous
Moonstone
Orthoclase Feldspar ((K,Na)AlSi3O8)
mineral
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic volcanic rock including secondary mineral infills)
Igneous
Vesicular Basalt
Extrusive mafic igneous rock
igneous
Satin Spar (commonly sold as Selenite)
Hydrous Calcium Sulfate (CaSO4·2H2O)
mineral
Blue Kyanite
Kyanite (Al2SiO5)
mineral
Quartzite (River Cobble)
Quartzite (SiO2)
metamorphic
Chert (specifically Red Chert/Jasper variety)
Silicon Dioxide (SiO2)
sedimentary
Diorite
Diorite (Intermediate intrusive igneous rock)
igneous
Nuummite
Nuummite (intergrowth of orthoamphiboles Anthophyllite and Gedrite, (Mg,Fe)7Si8O22(OH)2)
metamorphic
Blue Lace Agate
Chalcedony (Silicon Dioxide, SiO2)
mineral
Mica
Phlogopite or Biotite group (KMg3(AlSi3O10)(F,OH)2 / K(Mg,Fe)3AlSi3O10(OH)2)
mineral