Quartzite
Quartzite (mostly SiO2)
Category
Browse organic (often found by beachcombers) specimens identified by the Rock Identifier community.
Quartzite
Quartzite (mostly SiO2)
Magnetite (Iron Ore)
Magnetite (Fe3O4)
Siderite Concretion
Ironstone (Siderite) Concretion, FeCO3
Clear Quartz
Silicon Dioxide (SiO2)
Fossil Coral (Rugose)
Rugosa (Order), often preserved in Limestone (CaCO3)
Pink Quartzite
Quartzite (primarily SiO2)
Howlite
Howlite (Ca2B5SiO9(OH)5)
Limestone
Calcium Carbonate (CaCO3)
Picture Jasper
SiO2
Jade (Nephrite or Jadeite)
Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2) or Jadeite (Na(Al,Fe3+)Si2O6)
Sodalite
Na8(Al6Si6O24)Cl2
Yellow Quartzite
Quartzite (primarily SiO2)
Quartzite
Metamorphosed Quartz Sandstone (SiO2)
Quartzite
Quartzite (SiO2)
Larimar
NaCa2Si3O8(OH)
Almandine Garnet in Matrix
Almandine, Fe3Al2(SiO4)3
Fossiliferous Limestone
Limestone (composed primarily of calcite with included fossils CaCO3)
Sandstone (with Iron Siderite Concretion)
Arenite with Ironstone Concretion (FeCO3)
Sandstone
Arenite (primarily Quartz, SiO2)
Ferruginous Quartz
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Quartzite Pebble
Quartzite (primarily SiO2)
Quartz and Mixed Sedimentary Rocks
Silicon Dioxide (SiO2) mixed with various clastic sedimentary lithologies
Flesh-colored Quartzite
Quartzite (SiO2)
Sodalite
Sodalite (Na4Al3Si3O12Cl)
Magnetite
Magnetite (Iron(II,III) oxide, Fe3O4)
Transit Token (RTD Denver)
Nickel-plated brass or bronze alloy (Cu-Sn-Zn-Ni)
Sodalite
Sodalite (Na8Al6Si6O24Cl2)
Greenstone or Chlorite Schist
Greenschist / Chlorite schist
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Amazonite
K(AlSi3O8) - Potassium Aluminum Silicate
Gabbro Pebble
Gabbro (intrusive mafic rock)
Greenstone Pebble
Metabasalt (often containing chlorite, actinolite, or epidote)
Quartz (Milky or Cloudy Quartz)
Silicon Dioxide (SiO2)
Basalt (River Stone)
Afanitic Basalt (primarily Plagioclase Feldspar and Pyroxene)
Chert (Nodule)
Chert (variety of microcrystalline quartz, SiO2)
Bornite (Peacock Ore)
Bornite (Cu5FeS4)
Black Spinel
Magnesium Aluminum Oxide (MgAl2O4)
Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
Granite
Granite (a phaneritic intrusive igneous rock consisting mainly of quartz, alkali feldspar, and plagioclase)
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
Quartz Pebble
Quartz (Silicon Dioxide, SiO2)