Chalcedony (Common Opal variant)
Silicon dioxide (SiO2) with varying levels of hydration
Category
Browse industrial byproduct (often confused with igneous rocks or meteorites) specimens identified by the Rock Identifier community.
Chalcedony (Common Opal variant)
Silicon dioxide (SiO2) with varying levels of hydration
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 inclusions)
Milky Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Basalt with Secondary Mineralization (Likely Zeolites or Calcite)
Aphanitic mafic volcanic rock with secondary mineral inclusions (e.g., CaAl2Si3O10·3H2O for Scolecite)
Quartzite Pebble
Metamorphosed Quartz Sandstone (SiO2)
Granite Pegmatite
Coarse-grained Granite (SiO2 - Aluminum and Alkalies)
Rhodonite
Rhodonite; (Mn,Fe,Mg,Ca)SiO3
Calcite
Calcite (CaCO3)
Milky Quartz with Iron Staining
Quartz (Silicon Dioxide, SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Pyrite
Iron Disulfide (FeS2)
Ruby
Corundum (Al2O3 with Chromium traces)
Blue Sapphire
Corundum (Al2O3 with trace amounts of iron and titanium)
Brown Agate
Silicon Dioxide (SiO2)
Sodalite
Sodalite - Na8(Al6Si6O24)Cl2
Agate Geode
Chalcedony (SiO2 - Silicon Dioxide)
Epidote (or Epidote-rich rock)
Epidote. Mineral formula: Ca2(Al,Fe)3(SiO4)3(OH).
Quartz on Chlorite Schist
Chlorite Schist (Mg,Fe)3(Si,Al)4O10(OH)2 with Quartz (SiO2)
Vesicular Rhyolite
Extrusive igneous rock (high-silica rhyolite)
Blue Sapphire (in a faceted jewelry setting)
Corundum (Al2O3) with trace Iron and Titanium
Granite
Granite
Rough Quartz (var. Citrine or Yellow Quartz)
Silicon Dioxide (SiO2)
Black Tourmaline
Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)
Dark Igneous Rock (Likely Basalt or Diabase)
Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.
Corundum (Ruby variety)
Aluminium oxide (Al2O3)
Yellow Quartz (Citrine or Quartzite Pebble)
Silicon Dioxide (SiO2)
Quartz
Silicon dioxide (SiO2)
Greenschist
Chlorite schist
Milky Quartz
Silicon Dioxide (SiO2)
Granite Glacial Erratic
Granite (Phaneritic Quartz-Feldspar Plutonic Rock)
Apatite
Fluorapatite, Chlorapatite, and Hydroxylapatite (Ca5(PO4)3(F,Cl,OH))
Diamond in Kimberlite
Diamond in Kimberlite Matrix (Diamond: C, Kimberlite: complex Potassic Peridotite)
Sodalite
Sodium Aluminum Silicate Chloride (Na8(Al6Si6O24)Cl2)
Hypersthene
Enstatite (Hypersthene variety), (Mg,Fe)SiO3
Black Tourmaline
Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)
Sandstone (Ferruginous)
Arenite (composed primarily of SiO2 with Fe2O3 cement)
Magnetite
Magnetite (Fe3O4)
Black Star Diopside (beads)
Diopside (CaMgSi2O6) - a member of the pyroxene group
Rose Quartz
Silicon Dioxide (SiO2) with traces of Titanium, Iron, or Manganese
Quartz (Citrine or Iron-stained Quartz)
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Aquamarine
Beryl (Be3Al2Si6O18 with iron impurities)