Quartz (Quartzite fragment)
Silicon Dioxide (SiO2)
Category
Browse organic gemstone (not a rock or mineral in the traditional sense, but bio mineralized material) specimens identified by the Rock Identifier community.
Quartz (Quartzite fragment)
Silicon Dioxide (SiO2)
Pegmatite
Granitic Pegmatite
Garnet Schist or Garnet-bearing Quartzite
Metamorphic rock containing Almandine Garnet (Fe3Al2(SiO4)3) and Quartz (SiO2)
Ironstone (likely Limonite or Goethite)
Ferruginous sedimentary rock (FeO(OH)·nH2O)
Greenschist
Greenschist facies rock (containing chlorite, actinolite, albite, and epidote)
Hypersthene
Hypersthene ((Mg,Fe)SiO₃)
Clear Quartz Point
Silicon Dioxide (SiO2)
Carnelian (Agate)
SiO2 (Silicon Dioxide with Iron Oxide impurities)
Mica Schist
Mica Schist (predominantly Muscovite or Biotite sheet silicates)
Banded Agate
Cryptocrystalline Quartz (SiO2)
Quartz (Iron-stained)
Silicon Dioxide (SiO2) with Hematite/Limonite impurities
Sandstone (Ferruginous)
Arenite with Iron Oxide (Fe2O3) cement
Fulonite (Fulgurite-like)
Fulgurite (SiO2 fused silica/lechatelierite)
Diorite (Salt and Pepper Rock)
Phaneritic plutonic igneous rock (sodium-rich plagioclase feldspar and hornblende)
Quartz / Chert
Silicon Dioxide (SiO2)
Quartz
Quartz (SiO₂)
Milky Quartz with Matrix
Quartz (Silicon Dioxide, SiO2)
Quartzite with Quartz Vein
Metamorphosed Quartz-rich Arenite (SiO2)
Granite
Phaneritic Felsic Igneous Rock (primarily Quartz, Alkali Feldspar, and Plagioclase)
Quartz Pebble (Milky Quartz)
Silicon Dioxide (SiO2)
Quartz (chalcedony variety) or Limestone with Quartz Veins
SiO2 (for Quartz/Chalcedony); CaCO3 (for Limestone)
Chert (varietal Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Granite
Granite (Phaneritic intrusive igneous rock)
Agate (Carnelian/Chalcedony)
Silicon Dioxide (SiO2)
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
Carnelian (Red Chalcedony)
Silicon Dioxide (SiO2) - variety of Chalcedony
Tektite (likely Australite)
Tektite (no specific chemical formula as it's a natural glass of variable composition, mostly SiO2, Al2O3, FeO, MgO, CaO, K2O, Na2O, TiO2)
Laterite
Laterite (Ferricrete)
Yellow Agate
Chalcedony (cryptocrystalline silica), SiO2
Epidote in Basalt
Epidotized Basalt (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH) in Mafic Igneous Host)
Fossilized Gastropod (Snail)
Class Gastropoda (internal mold or 'steinkern')
Smoky Quartz
Silicon Dioxide (SiO2)
Petrified Wood
Silicified wood (Quartz/Chalcedony)
Quartz with Iron Stains
Quartz (SiO2) with iron oxide/hydroxide staining
Goldstone
Avventurina (Cu + SiO2 glass)
Man-made Synthetic Material (Costume Faux Fur)
Synthetic Polymer (Polyester/Acrylic)
Staurolite (Fairy Stone)
Staurolite (Fe2+2Al9Si4O23(OH))
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
Clear Quartz
Silicon Dioxide (SiO2)
Carnelian Agate
Silicon Dioxide (SiO2)
Yellow Quartzite River Cobble
Meta-quartzite (SiO2 with iron oxide staining)
Sandstone (Quartzose)
Arenite (composed primarily of SiO2)