Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Category
Organic (Often Found By Beachcombers)
Browse organic (often found by beachcombers) specimens identified by the Rock Identifier community.
Quartzite Pebble (River Rock)
Quartzite (primarily SiO2)
metamorphic
Pink Quartzite
Quartzite (primarily SiO2)
metamorphic
Firewood (Wood Log)
Lignum (Plant tissue composed of cellulose and lignin)
Organic (Non-geological)
Ferruginous Sandstone (Ironstone Conglomerate fragments)
Ferruginous clastic sedimentary rock (SiO2 cemented by Fe2O3)
sedimentary
Jasper
Jasper (Silicified microcrystalline quartz) - SiO2
sedimentary
Green Calcite
Calcium Carbonate (CaCO3)
mineral
Sodalite
Na8(Al6Si6O24)Cl2
mineral
Fossilized Shark Tooth (Otodus obliquus)
Otodus obliquus (Mineral composition: Bio-apatite/Calcium Phosphate replaced by various minerals)
sedimentary (fossil)
Amethyst
Amethyst (SiO2 - Silicon Dioxide with Iron impurities)
mineral
Rose Quartz
SiO2 (Silicon Dioxide with trace inclusions of dumortierite)
mineral
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic Volcanic Rock)
igneous
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Chert (or Chalcedony)
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Chert (specifically White Chert or Novaculite)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Greyling Sandstone / Greywacke
Lithic Wacke (SiO2 + diverse mineral fragments)
sedimentary
Chert (and Flint variant)
Silicon Dioxide (SiO2)
sedimentary
Chert (or Flint)
Mocrocrystalline Quartz (SiO2)
sedimentary
Chert (Flint)
Chert (Silicon Dioxide, SiO2)
sedimentary
Green Glass (often marketed as 'Obsidian' or 'Green Quartz')
Amorphous Silica (SiO2) with copper or chromium additives
Mineraloid (Man-made)
Ferruginous Quartz
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Mineral
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
mineral
Scoria (Lava Rock)
Scoria (Vesicular Basaltic Glass/Rock)
igneous
Quartz Vein in Host Rock (Likely Slate or Shale)
Hydrothermal Quartz (SiO2) in Pelitic host rock
metamorphic
Quartz (Float/Abraded)
Quartz (SiO₂)
Mineral
Quartzite
Quartzite (mostly SiO2)
metamorphic
Quartzite Pebble
Quartzite (SiO2 with minor impurities)
metamorphic
Yellow Calcite
Calcium Carbonate (CaCO3)
mineral
Serpentine (Greenstone)
Antigorite, Lizardite, and Chrysolite mixture (Mg3Si2O5(OH)4)
metamorphic
Eudialyte
Eudialyte (Na4(Ca,Ce)2(Fe2+,Mn,Y)ZrSi8O22(OH,Cl)2)
mineral
Quartzite
Quartzite (primarily SiO2)
metamorphic
Beryl (Variety: Aquamarine)
Beryllium Aluminum Cyclosilicate (Be3Al2Si6O18)
mineral
Conglomerate
Conglomeratic Sandstone / Sedimentary Breccia
sedimentary
Fulgurite
Luechatelierite (SiO2 glass)
mineraloid
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
mineral
Malachite with Chrysocolla
Copper carbonate hydroxide (Cu2CO3(OH)2) and Hydrated copper silicate (Cu,Al)2H2Si2O5(OH)4·nH2O
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Quartzite
Quartzite (primarily SiO2)
metamorphic
Green Aventurine
Quartz (SiO2) with Fuchsite inclusions
Mineral
Turquoise (Dyed Howlite/Magnesite imitation)
CuAl6(PO4)4(OH)8·4H2O (Target mineral) / Ca2B5SiO9(OH)5 (Actual specimen: Howlite)
mineral
Quartzite (River Stone)
Quartzite (composed primarily of Silicon Dioxide, SiO2)
metamorphic
Sandstone
Arenite
sedimentary