Amethyst (Tumbled)
Quartz (Silicon Dioxide, SiO2) with iron impurities
Category
Browse organic structure (not a rock) specimens identified by the Rock Identifier community.
Amethyst (Tumbled)
Quartz (Silicon Dioxide, SiO2) with iron impurities
Red Jasper (Polished)
Silicon Dioxide (SiO2) with Hematite inclusions
Granite
Granite (Mainly Quartz, Alkali Feldspar, and Plagioclase)
Banded Agate (Tumbled)
Agate (Variety of Chalcedony/Quartz), SiO2
Pumice
Pumice (Vesicular volcanic glass / Rhyolite or Trachyte)
Chert (vuggy/nodular)
Microcrystalline Quartz (SiO2)
Amber
Succinite
Sandstone
Arenite (primarily SiO2)
Basalt
Basalt (dominated by Plagioclase Feldspar and Pyroxene)
Quartz (Sand Grain size)
Silicon Dioxide (SiO2)
Quartzite
Metamorphosed Quartz Sandstone (SiO2)
Tiger's Eye (Inlaid in a band)
SiO2 (Silicon Dioxide with Crocidolite inclusions)
Milky Quartz
Silicon Dioxide (SiO2)
Quartz Vein / Milky Quartz
Silicon Dioxide (SiO2)
Quartz Crystal
Silicon Dioxide (SiO2)
Turquoise
Hydrated phosphate of copper and aluminium: CuAl6(PO4)4(OH)8·4H2O
Amethyst (Rough Quartz)
Silicon Dioxide (SiO2) with iron impurities
Quartz Geode
Silicon Dioxide (SiO2)
Sandstone
Clastic sedimentary rock (primarily SiO2)
Sunstone (variety of Feldspar)
Oligoclase Sunstone, Plagioclase Feldspar (Na,Ca)Al(Si,Al)Si2O8
Amber
Succinite
Fulgurite
Luechatelierite (SiO2 glass)
Sandstone (likely Ferruginous)
Arenite (SiO2 with iron oxide impurities)
Sandstone (Quartzose Sandstone)
Arenite (SiO2 primarily)
Quartzite
Quartzite (SiO2)
Blue Chalcedony
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)
Sandstone
Arenite (primarily SiO2 with various cementing agents)
Pyrite in Shale
Iron Sulfide (FeS2)
Sandstone (Calcareous Sandstone)
Calcareous Sandstone (primarily SiO2 with CaCO3 cement)
Limonite Concretion
Limonite (Hydrated Iron Oxide) FeO(OH)·nH2O
Quartzite
Quartzite (composed primarily of SiO2)
Sandstone (Quartzose Sandstone)
Arenite
Quartzite
Quartzite (primarily SiO2)
Labradorite (Larvikite variety)
Ternary feldspar (Anorthoclase), (Na,K)AlSi3O8
Granite (weathered pebble)
Granite (plutonic igneous rock)
Amber
Succinite (fossilized resin)
Pearl (in a decorative hair comb setting)
Calcium carbonate (CaCO3) primarily as Aragonite, bonded with Conchiolin
Amber
Succinite (a specific high-quality amber from the Baltic)
Agate
Silicon dioxide (SiO2)
Sandstone
Arenite (SiO2 based typically)
Banded Calcite (often sold as 'Mexican Onyx')
Calcite (Calcium Carbonate, CaCO3)