Lake Superior Agate
Agate (Cryptocrystalline variety of Quartz, SiO2)
Category
Browse mineral (pseudomorph) specimens identified by the Rock Identifier community.
Lake Superior Agate
Agate (Cryptocrystalline variety of Quartz, SiO2)
Amazonite
Microcline (KAlSi3O8) with lead impurities
Citrine
Crystalline Quartz (SiO2) with iron impurities
Emerald
Beryl (Be3Al2(SiO3)6) with chromium/vanadium impurities
Granite
Granite
Yellow Jasper
Chalcedony (Silicon Dioxide with Iron inclusions), SiO2
Basalt (River Rock/Cobble)
Basalt (no specific mineral formula as it's a rock)
Granite fragment
Felsic intrusive igneous rock; mainly quartz, alkali feldspar, plagioclase, and minor biotite/hornblende
Quartz Boulder
Silicon Dioxide (SiO2)
Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Quartz pebble
Silicon dioxide (SiO2)
Magnetite-rich Basalt
Basalt containing Fe3O4
Bauxite
Aluminum ore (mixture of gibbsite Al(OH)3, boehmite γ-AlO(OH), and diaspore α-AlO(OH))
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz and Mixed Sedimentary Rocks
Silicon Dioxide (SiO2) mixed with various clastic sedimentary lithologies
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Quartz Pebble
Silicon Dioxide (SiO2)
Bauxite
Bauxite (Mixture of Al(OH)3, AlO(OH), and Fe2O3)
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
Ruby in Kyanite
Corundum in Disthene (Al2SiO5 + Al2O3)
Fluorite (Green)
Calcium Fluoride (CaF2)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Limonite (Iron Ore)
Hydrous ferric oxides (FeO(OH)·nH2O)
Mahogany Obsidian
Obsidian with Hematite inclusions (SiO2 + Fe2O3)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz pebble
Silicon dioxide (SiO2)
Quartz (River Pebble)
Silicon Dioxide (SiO2)
Limonite (Ironstone Concretion)
Limonite (Hydrated iron(III) oxide-hydroxide, mixtures of FeO(OH)·nH2O)
Quartz pebble
Silicon Dioxide (SiO2)
Quartz (Small Pebble)
Silicon Dioxide (SiO2)
Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Quartz (Grain)
Silicon Dioxide (SiO2)
Sandstone
Arenite (Silicon Dioxide with various mineral cements)
Sandstone (Greywacke/Siltstone variant)
Arenite / Wacke (SiO2 with diverse mineral inclusions)
Granite
Intrusive Igneous Rock (Felsic)
Mica Schist
Mica Schist (predominantly Muscovite or Biotite sheet silicates)
Sandstone
Clastic sedimentary rock
Fluorite
Calcium Fluoride (CaF2)
Olivine
(Mg,Fe)2SiO4
Mystic Topaz (Treated Quartz or Topaz)
Aluminum silicate fluoride hydroxide [Al2SiO4(F,OH)2] with thin-film metallic coating