Chert (Arrowhead or Projectile Point)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Category
Browse synthetic or natural fiber specimens identified by the Rock Identifier community.
Chert (Arrowhead or Projectile Point)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Smoky Quartz and Chalcedony Geode Fragment
Silicon Dioxide (SiO2)
Banded Agate (River Stone)
Agate (Silicon Dioxide - SiO2)
Beryl (Emerald or Aquamarine in Matrix)
Beryllium Aluminum Silicate (Be3Al2Si6O18)
Citrine
Quartz (SiO₂)
Obsidian
Obsidian (Extrusive Volcanic Glass)
Basalt River Cobble
Basalt (Aphanitic Mafic Volcanic Rock)
Ferruginous Conglomerate
Ferruginous Conglomerate (Clastic Sedimentary Rock)
Slag Glass (Cullet)
Amorphous Silica / Glass residue
Obsidian (Apache Tear)
Obsidian / Amorphous Volcanic Glass (main component: SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Clear Quartz
Silicon Dioxide (SiO2)
Banded Quartzite River Pebble
Metamorphosed Quartz-rich Sandstone (SiO2)
Quartzite Pebble
Quartzite (primarily SiO2)
Amethyst
Amethyst (SiO2 with Iron impurities)
Smoky Quartz
Silicon Dioxide (SiO2)
Red Jasper
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Rainbow Hematite (Man-made/Treated)
Tumbled Hematite with Titanium/Anodized coating (Iron(III) oxide, Fe2O3)
Smoky Quartz
Silicon Dioxide (SiO2)
Dyed Quartzite
Tumbled Metamorphosed Quartz (SiO2) with artificial pigment
Agate (specifically, multi-colored or pastel-dyed agate)
Silicon dioxide (SiO2) - specifically, a cryptocrystalline variety of quartz known as Chalcedony, with banding classified as Agate. (If it were Fluorite, the chemical formula would be Calcium Fluoride - CaF2).
Laterite (iron-rich nodule, possibly Bauxite as a subtype)
Laterite (composed of various minerals including goethite, hematite, gibbsite, etc.)
Rough Corundum (likely Sapphire/Zircon-bearing)
Aluminium Oxide (Al2O3)
Blue Sapphire (Ceylon)
Corundum (Al2O3) with traces of Iron and Titanium
Smoky Quartz
Silicon Dioxide (SiO2)
Yellow Quartz Pebble
Silicon Dioxide (SiO2)
River Stone (likely Mudstone or Siltstone)
Lutite (Clastic sedimentary rock composed of clay and silt-sized particles)
Sandstone
Arenite (composed primarily of Quartz: SiO2)
Diamond (in Gold Jewelry)
Carbon (C)
Herkimer Diamond
Quartz (SiO2)
Diamond (set in Gold)
Carbon (C)
Smoky Quartz
Silicon Dioxide (SiO2)
Nephrite Jade
Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)
Travertine
Travertine (CaCO3 - Calcium Carbonate)
Apache Tear (Obsidian)
Obsidian / Amorphous Volcanic Glass (primarily SiO2)
Ruby
Corundum (Al2O3 with Chromium impurities)
Turquoise (Rough Specimens)
Hydrous phosphate of copper and aluminium - CuAl6(PO4)4(OH)8·4H2O
Fluorite (Blue)
Calcium Fluoride (CaF2)
Moldavite
Silica glass with small amounts of aluminum, iron, and other elements
Chrysocolla
Hydrated copper silicates (Cu,Al)2H2Si2O5(OH)4·nH2O
Green Aventurine
Quartz (Silicon Dioxide) with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)