Rough Star Sapphire (Corundum)
Al2O3 (Aluminum Oxide)
Category
Browse organic gemstone (not a rock or mineral in the traditional sense, but bio mineralized material) specimens identified by the Rock Identifier community.
Rough Star Sapphire (Corundum)
Al2O3 (Aluminum Oxide)
Prehnite on Basalt
Prehnite - Ca2Al(AlSi3O10)(OH)2
Slag (Industrial Byproduct)
Artificial silicate/iron byproduct
Milky Quartz (or Iron-Stained Quartz)
Quartz (Silicon Dioxide, SiO2)
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with iron inclusions)
Rough Aquamarine
Beryl (Be₃Al₂Si₆O‑₁•H₂O)
Turquoise
Hydrated phosphate of copper and aluminium, CuAl6(PO4)4(OH)8·4H2O
Basalt
Basalt (Aphanitic mafic volcanic rock)
Amethyst
Amethyst (Silicon Dioxide with Iron impurities, SiO2)
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Citrine Geode Fragment
Citrine (Silicon Dioxide with Iron Impurities), SiO2
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Ruby in Fuchsite
Corundum (Al2O3) in Fuchsite (K(Al,Cr)3Si3O10(OH)2)
Granite
Granite (felsic intrusive igneous rock)
Milky Quartz
Silicon Dioxide (SiO2)
Greenstone (Epidote/Chlorite-rich Metabasalt)
Greenschist / Epidosite (Ca2(Al,Fe)3(SiO4)3(OH))
Diamond (Green tinted)
Carbon (C) with trace impurities or lattice defects
Turquoise
Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]
Quartz (Specifically Clear to Smoky Quartz point)
Silicon Dioxide (SiO2)
Diorite
Diorite (Intermediate intrusive igneous rock)
Quartz (milky quartz variety)
Quartz (SiO₂)
Amber
Succinite (fossilized tree resin)
Sandstone
Arenite (primarily SiO2)
Petrified Wood
Silicified wood (primarily Silicon Dioxide - SiO2)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with iron oxide staining/cementing)
Sandstone (with Iron Staining)
Arenite (composed primarily of SiO2 with Fe2O3 staining)
Quartz (likely)
Quartz (SiO2 - Silicon Dioxide)
Siltstone/Sandstone (possibly Wonderstone or Picture Sandstone)
Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide inclusions)
Smoky Quartz
Silicon Dioxide (SiO2)
Clear Quartz
Silicon Dioxide (SiO2)
Quartz
Silicon Dioxide (SiO2)
Carnelian
Carnelian Chalcedony (SiO2 with iron oxide impurities)
Malachite
Copper carbonate hydroxide [Cu2CO3(OH)2]
Sodalite
Sodalite (Na8Al6Si6O24Cl2)
Milky Quartz
Silicon Dioxide (SiO2)
Amethyst
Amethyst (Silicon Dioxide, SiO2 + Fe)
River Pebble (Likely Chert or Fine-Grained Sandstone/Quartzite)
Siliciclastic clast (likely Chert or Quartzarenite/Quartzite pebble)
Smoky Quartz
Silicon Dioxide (SiO2)
Diamond (Princess Cut Gemstone)
Carbon (C)
Blue Sapphire
Corundum (Al2O3)
Amethyst
SiO2 (Silicon Dioxide with iron impurities)