Sandstone Concretion
Sedimentary concretion
Category
Browse not a natural rock (man made composite) specimens identified by the Rock Identifier community.
Sandstone Concretion
Sedimentary concretion
Diamond
Diamond (pure carbon C)
Tumbled blue-green stone, likely chrysocolla or dyed chalcedony
Probable chrysocolla (hydrated copper aluminosilicate; variable composition), though appearance could also represent dyed chalcedony
Green Aura Quartz
Silicon Dioxide (SiO2) bonded with metallic vapors (typically Gold, Chromium, or Titanium)
Obsidian
Obsidian (volcanic glass, amorphous silica rich rock)
Diamond
Carbon (C)
Diamond
Diamond (Pure Carbon, C)
Dyed Quartz (often sold as 'Blue Quartz' or 'Blue Agate')
Silicon Dioxide (SiO2) with artificial pigment
Diamond
Carbon (C)
Raw Diamond
Carbon (C)
Pearl
Calcium Carbonate (mostly Aragonite), CaCO3 (with conchiolin)
Diamond (in jewelry setting)
Carbon (C)
Diamond (in jewelry setting)
Adamantine Carbon (C)
Granite
Granite (a plutonic igneous rock)
Lava Rock (Dyed)
Basalt / Volcanic scoria
Pearl (Biogenic Mineraloid)
Calcium carbonate (CaCO3) primarily as Aragonite
Pumice
Pumice (Vitreous volcanic rock)
Diamond (Cut Gemstone)
Natural Carbon (C)
Graphite
Graphite (Carbon, C)
Pearl
Biogenic CaCO3 (Aragonite and Calcite)
Dyed Quartz (imitating Emerald/Green Quartz)
Silicon Dioxide (SiO2) with artificial pigment
Rutilated Quartz
Silicon Dioxide (SiO2) with Titanium Dioxide (TiO2) inclusions
Quartz (Smoky Quartz variant)
Silicon Dioxide (SiO2)
Natural Pearl (appearing in a jewelry setting)
Calcium Carbonate (mostly Aragonite), CaCO3 with Conchiolin
Diamond (or Cubic Zirconia)
Carbon (C) or Zirconium Dioxide (ZrO2)
Unknown Tumbled Stone
Unknown (Too Blurry)
Amethyst
Silicon Dioxide (SiO2)
Turquoise (likely stabilized or simulated Howlite)
CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminium)
Diamond (in a jewelry setting)
Cubic Carbon (C)
Pearl (Biogenic)
Nacre / Calcium Carbonate (CaCO3)
Painted Rock / Geode Specimen
Silicon Dioxide with artificial pigment coating
Diamond
Natural Diamond (Carbon, C)
Granite
Plutonic Igneous Rock (composed typically of SiO2, Al2O3, K2O, Na2O, CaO)
Pearl and Garnet Glass
Calcium Carbonate (CaCO3) for pearl; Silicon Dioxide (SiO2) for glass
Coquina
Bioclastic Limestone (composed primarily of CaCO3)
Banded Chert / Chalcedony
Silicon Dioxide (SiO2)
Coquina / Fossiliferous Limestone
Coquina (composed primarily of Calcium Carbonate / CaCO3)
Corundum (Sapphire variant)
Aluminium oxide (Al2O3)
Red gemstone ring, likely garnet or synthetic ruby
Possibly almandine garnet (Fe₃Al₂(SiO₄)₃) or corundum/ruby (Al₂O₃); image alone cannot distinguish
Green Aura Quartz (Titanium treated Kyanite or Quartz)
Silicon Dioxide (SiO2) or Aluminum Silicate (Al2SiO5) with Titanium/Metal Oxide coating
Granite / Diorite (Granodiorite)
Granodiorite / Quartz Diorite
Glass / Silicon Dioxide (Man-made)
SiO2 (Amorphous Silicon Dioxide)