Basalt
Extrusive mafic igneous rock
Category
Browse industrial byproduct (often mistaken for obsidian or mineral) specimens identified by the Rock Identifier community.
Basalt
Extrusive mafic igneous rock
Quartzite
Silicon Dioxide (SiO2)
Chert (Jasper/Flint variety)
Silicon Dioxide (SiO2)
Ruby
Corundum (Al₂O₃) with Chromium (Cr)
Schist
Mica Schist
Pegmatite
Granitic Pegmatite
Anthracite
Anthracite Coal
Blue Sapphire
Corundum (Al2O3) with traces of Iron and Titanium
Basalt
Basalt
Unidentified Rock Fragment
Unknown
Chert (often called Flint or Jasper)
Silicon Dioxide (SiO2)
Chert (Gravel pebble)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Quartzite
Quartzite (primarily SiO2)
Quartzite
Quartzite (SiO2)
Granite (Pegmatitic)
Phaneritic Felsic Igneous Rock
Common Opal
Amorphous Hydrated Silica (SiO2·nH2O)
Clear Quartz (Rock Crystal)
Quartz (Silicon Dioxide - SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartzite
Metamorphosed Quartz Sandstone
Chert with Druzy Quartz Geode
Microcrystalline Quartz (SiO2)
Limestone
Calcium Carbonate (CaCO3)
Chert (specifically Gray/Blue-Gray Chert)
Chert (SiO2)
Chert (Nodule)
Silicon Dioxide (SiO2)
Quartzite
Quartzite (SiO2)
Diamond (Faceted Gemstone)
Native Carbon (C)
Muscovite Mica (in Quartz matrix)
Potassium aluminum silicate hydroxide fluoride (KAl2(AlSi3O10)(F,OH)2)
Black Tourmaline
Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)
Milky Quartz Pebble
Silicon Dioxide (SiO2)
Diamond (in a jewelry setting)
Carbon (C)
Shungite
Shungite (Non-crystalline carbon, C)
Quartz Pebble (Water-Worn)
Silicon Dioxide (SiO2)
Peridot
Olivine (Magnesium Iron Silicate - (Mg, Fe)2SiO4)
Peridot (Olivine)
Olivine, (Mg, Fe)2SiO4
Diamond (appearing in jewelry)
Diamond (pure Carbon, C)
Aqua Aura Quartz
Titanium/Gold-coated Silicon Dioxide (SiO2)
Black Tourmaline
Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)
White Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Cubic Zirconia (CZ) in Gold-Plated Setting
Cubic Zirconium Dioxide (ZrO2)
Gold Nugget
Native Gold (Au)
Schist
Mica Schist
Diamond
Native Carbon (C)
Sandstone (Pebble)
Arenite (primarily SiO2)