Sandstone (likely Quartzose Sandstone)
Arenite (SiO2 predominantly)
Category
Browse industrial byproduct (often mistaken for obsidian or mineral) specimens identified by the Rock Identifier community.
Sandstone (likely Quartzose Sandstone)
Arenite (SiO2 predominantly)
Quartzite
Quartzite (SiO2)
Peridot (Olivine)
Olivine ((Mg,Fe)2SiO4)
Jasper, Agate, Quartz Mix (Polished Beads)
SiO₂ (Silicon Dioxide) for Quartz. Jasper and Agate are cryptocrystalline varieties of Quartz.
Garnet Gneiss
Gneiss containing almandine-pyrope garnet
Quartz Geode
Silicon Dioxide (SiO2) within a geode
Diamond
Carbon (C)
Yellow Diamond (Faceted)
Diamond (pure carbon) with nitrogen impurities, C
Angelite
Anhydrite (Calcium Sulfate, CaSO4)
Yellow Calcite
Calcium Carbonate (CaCO3)
Orange Quartz (Citrine Quartz)
Silicon Dioxide (SiO2)
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
Citrine Quartz
Crystalline Quartz (SiO2 with iron impurities)
Chromium (Chrome)
Chromium (Cr)
Diamond
Carbon (C)
Yellow Diamond
Diamond (Carbon, C)
Almandine Garnet
Almandine (Fe3Al2Si3O12)
Quartz Pebble
Silicon Dioxide (SiO2)
Blue Sapphire
Corundum (Al2O3 with trace Titanium and Iron)
Diamond (in a jewelry setting)
Carbon (C)
Chalcedony (Common Opal or Agate variant)
Silicon Dioxide (SiO₂)
Diamond (in jewelry setting)
Diamond (Native Carbon, C)
Diamond
Carbon (C)
Amethyst
Silicon dioxide (SiO2)
Sulfur (in host rock)
Native Sulfur (S8)
Quartz (Milky Quartz Pebble)
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Diamond
Diamond (C)
Man-made earbud charging case (Not a rock or mineral)
Acrylonitrile Butadiene Styrene (ABS) Plastic with electronic components
Diamond (Cut Specimen)
Carbon (C)
Red Jasper
Silicon Dioxide (SiO2) with Iron inclusions
Aragonite Star Cluster (or Aragonite Sputnik)
Aragonite (Orthorhombic Calcium Carbonate, CaCO3)
Basalt (Porphyritic)
Basalt (Mafic Extrusive Igneous Rock)
Banded Iron Formation
Banded Iron Formation (BIF)
Quartzite (or Milky Quartz pebble)
Quartzite (primarily Silicon Dioxide, SiO2)
Orange Quartzite (River Pebble)
Quartzite (primarily SiO2)
Epidote in Basalt
Epidotized Basalt (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH) in Mafic Igneous Host)
Banded Agate (with possible Chalcedony layers)
Silicon dioxide (SiO2)
Sapphire
Corundum (Al₂O₃) with trace elements causing color variations.
Quartz on Greenstone
Silicon Dioxide (SiO2) on Altered Igneous Geologic Unit
Garnet-Mica Schist
Garnetiferous Porphyroblastic Schist
Iron Ore (Limonite and Hematite)
Goethite/Limonite (FeO(OH)·nH2O) and Hematite (Fe2O3)