Chert (often called Flint for darker varieties)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Category
Browse not a natural rock (man made composite) specimens identified by the Rock Identifier community.
Chert (often called Flint for darker varieties)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Fossilized Horn Coral
Order Rugosa (Rugose Coral)
Quartz (Rose or Clear variety)
Silicon Dioxide (SiO2)
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
Green Fluorite
Fluorite (Calcium Fluoride - CaF2)
Moss Agate
Chalcedony (SiO2) with inclusions of manganese or iron oxide
Obsidian
Volcanic glass (high silica volcanic rock)
Grey Agate (Tumbled)
Silicon Dioxide (SiO2)
Moss Agate
Chalcedony (Silicon Dioxide) with dendritic inclusions (SiO2)
Limonite/Goethite (Iron Ore)
Hydrous ferric oxides (FeO(OH)·nH2O)
Tree Agate
Silicon Dioxide (SiO2)
Quartzite Pebble
Metamorphosed Quartz Sandstone (SiO2)
Sandstone (Ferruginous)
Sandstone (mainly SiO2 with Fe2O3 staining)
Jasper (Mookaite style)
Jasper (Silica-rich Microcrystalline Quartz, SiO2)
Agate (River Pea)
Microcrystalline Chalcedony (SiO2)
Apricot Agate
Silicon Dioxide (SiO2) - Chalcedony variety
Calcite
Calcite (Calcium Carbonate, CaCO3)
Pearl (Biogenic Mineraloid)
Calcium carbonate (Aragonite) and Conchiolin, CaCO3
Fossiliferous Limestone
Fossiliferous Calclutite / Bio-calcarenite (CaCO3)
Amethyst
SiO2 (Amethyst is a variety of Quartz)
Quartzite
Quartzite (primarily SiO2)
Rhodonite
Manganese Silicate (Mn,Fe,Mg,Ca)SiO3
Fluorite
Calcium Fluoride (CaF2)
Quartzite
Quartzite (SiO2)
Red Jasper
Jasper (Silicon Dioxide with Iron Oxide impurities), formula: SiO2
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (70% or more silicon dioxide)
Quartzite
Quartzite (SiO2 principal component)
Moss Agate
Chalcedony (SiO2) with inclusions of manganese or iron oxides
Turquoise
Hydrated phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O
Orthoclase Feldspar (Sunstone variety)
KAlSi3O8 (Potassium Aluminum Silicate)
Dyed Magnesite (often sold as Red Turquoise or Howlite)
Magnesium Carbonate (MgCO3)
Clear Quartz
Silicon Dioxide (SiO2)
Amygdaloidal Basalt
Amygdaloidal Basalt (Ca-rich Plagioclase, Pyroxene, and Olivine)
Granite
Granite (composed mainly of Quartz, Feldspar, and Mica)
Green Fluorite
Fluorite (Calcium Fluoride - CaF2)
Turquoise (likely Stabilized or Dyed Howlite/Magnesite)
Hydrated phosphate of copper and aluminium - CuAl6(PO4)4(OH)8·4H2O
Fluorite (translucent octahedral crystal)
Calcium fluoride (CaF2)
Quartzite
Quartzite (primarily SiO2)
Quartz Geode
Silicon Dioxide (SiO2) in Geode form
Quartzite
Quartzite (SiO2)
Red Jasper
Jasper (SiO2 with Fe2O3 inclusions)
Chert (or Flint)
Silicon dioxide (SiO2)