Quartzite
Quartzite (primarily SiO2)
Category
Browse sedimentary or metamorphic derived specimens identified by the Rock Identifier community.
Quartzite
Quartzite (primarily SiO2)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Quartz (beads)
SiO2 (Silicon Dioxide)
Milky Quartz
Silicon Dioxide (SiO2)
Quartz (Milky/Gravel variety)
Silicon Dioxide (SiO2)
Banded Gneiss
Gneiss (variable mineral composition)
Anthracite Coal
Anthracite (Carbon-rich metamorphic coal)
Banded Agate (Carnelian variety)
Cryptocrystalline Quartz (SiO2)
Sapphire
Corundum (Al2O3)
Agate (specifically Botswana or Lake Superior style Agate)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Rough Green Tourmaline (Verdelite)
Elbaite (Complex Silicate) - Na(Li,Al)3Al6(BO3)3Si6O18(OH)4
Smoky Quartz
Quartz (Silicon Dioxide) - SiO2
Black Sand (Magnetite Sand)
Magnetite (Fe3O4)
Micaceous Rock (likely Muscovite Schist/Gneiss or a Muscovite-rich Specimen)
Predominantly Muscovite (KAl2(AlSi3O10)(F,OH)2), often found in rocks like Muscovite Schist or Muscovite Gneiss.
Graphite
Graphite (C)
River Pebble (likely Quartzite or Chert)
Silicon Dioxide (SiO2)
Pyrite in Quartz
Iron Sulfide (FeS2) in Silicon Dioxide (SiO2)
Petrified Wood
Silicified wood (Quartz, SiO2)
Petrified Wood
Silicified Wood (primarily Quartz / Chalcedony: SiO2)
Titanium Quartz (Rough)
Titanium-included Silicon Dioxide (SiO2 + Ti)
Orange Quartz (Citrine Quartz)
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Yellow Quartz (Citrine or Iron-Stained Quartz)
Silicon Dioxide (SiO2)
Chrysanthemum Stone
Celestine (SrSO4) or Calcite (CaCO3) in Limestone/Porphyry matrix
Smoky Quartz (with Druzy/Polished Edge)
Smoky Quartz (Silicon Dioxide, SiO2)
Green Quartz (Aventurine)
Silicon Dioxide with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)
Milky Quartz (Water-Worn Pebble)
Silicon Dioxide (SiO2)
Banded Agate (Pink/Peach Chalcedony)
Agate (Silicon Dioxide, SiO2)
Citrine
Silicon Dioxide (SiO2) with iron impurities
Rough Citrine Quartz
Silicon Dioxide (SiO2) with ferric iron impurities
Garnet (Red Garnet)
Garnet Group. The red varieties seen in jewelry are typically Almandine (Fe3Al2(SiO4)3), Pyrope (Mg3Al2(SiO4)3), or a mix of the two (pyrope-almandine series).
Amethyst
Amethyst (Silicon Dioxide, SiO2)
Milky Quartz (Crystal Cluster)
Silicon Dioxide (SiO2) - Quartz Variety
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Quartz (likely tumbled or naturally water-worn)
Quartz (SiO₂ - Silicon Dioxide)
Magnetite (Iron Ore)
Magnetite (Fe3O4)
Greenschist
Greenschist facies rock
Petrified Wood
Silicified Wood (primarily SiO₂ - Silicon Dioxide)
Pyrite
Pyrite (FeS2)