Sandstone
Arenite (Sedimentary rock composed of sand-sized grains, primarily SiO2)
sedimentary
Category
Synthetic Or Natural Fiber
Browse synthetic or natural fiber specimens identified by the Rock Identifier community.
Sandstone
Arenite (SiO2 based clastic rock)
sedimentary
Green Aventurine
Aventurine Quartz (SiO2 with inclusions of Fuchsite)
Mineral
Green Aventurine
Aventurine Quartz (SiO2 with Fuchsite inclusions)
mineral
Blue Quartzite (Aventurine)
Quartzite (primarily SiO2) with inclusions of Dumortierite or Magnesio-riebeckite
metamorphic
Yellow Ocher (Limonite)
Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O
mineral
Tufa
Calcareous Tufa (CaCO3)
sedimentary
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Fossiliferous Limestone (Coral Fossil)
Scleractinian Coral in Calcium Carbonate (CaCO3)
sedimentary
Chert Concretion (with typical hematite/limonite staining)
Sedimentary Concretion (SiO2 with FeO(OH)⋅nH2O)
sedimentary
Black Pearl (Tahitian or Irradiated Type)
Organic gemstone (Calcium Carbonate with Conchiolin Binding)
mineraloid
Amber
Succinite (Fossilized Tree Resin) - C10H16O
mineral
Ironstone Concretion (Iron-rich Mudstone)
Siderite / Geothite concretion (FeCO3 / FeO(OH))
sedimentary
Native Copper (in coinage alloy)
Copper (Cu)
mineral
Smoky Quartz (Rough Specimen)
Silicon Dioxide (SiO2)
mineral
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Chert (Arrowhead Artifact)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Pink Granite
Granite (Felsic Plutonic Rock)
igneous
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with Iron inclusions)
metamorphic
Jasper Breccia
Brecciated Jasper (Silicon Dioxide with Iron Oxide inclusions, SiO2)
sedimentary
Moonstone
Orthoclase Feldspar (formula: (K,Na)AlSi3O8)
mineral
Agate (or Chalcedony)
SiO2 (Silicon Dioxide) - a cryptocrystalline variety of quartz
Mineral
River Quartzite or Chert Pebble
Quartzite (primarily Silicon Dioxide - SiO2)
metamorphic
Grey River Pebble (Likely Quartz-rich or Limestone)
Clastic Sedimentary Rock (typically SiO2 or CaCO3 based)
sedimentary
Corundum (Ruby/Sapphire crystal)
Al2O3 (Aluminum Oxide)
mineral
Ferrosilicon Slag (Industrial Vitrified Glass)
Vitreous Silicate Residue
Antropogenic (Man-made industrial byproduct)
Ironstone Concretion / Goethite Nodules
Ironstone (composed primarily of Goethite FeO(OH) and Limonite)
sedimentary
Gastly (Trick or Trade Halloween Series)
Cellulose-carbonaceous composite (Lignocellulose laminated with pigmentary polymers)
Mineral (Synthetic - Paper and Ink Polymorph)
Amethyst (Agate/Chalcedony variety)
Silicon Dioxide (SiO2) with iron impurities
mineral
Botryoidal Aragonite (Cave Popcorn)
Aragonite (Calcium Carbonate, CaCO3)
mineral
Granite
Phaneritic Felsic Igneous Rock (primarily Quartz, Feldspar, and Mica)
igneous
Amethyst Geode (Carved)
Amethyst (Violet Crystalline Quartz - SiO2)
mineral
Pink Quartzite
Metamorphosed Quartz Arenite (SiO2)
metamorphic
Granite
Phaneritic Igneous Rock (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Granitic Pegmatite with Schorl Tourmaline
Granitic Pegmatite (Schorl: NaFe3Al6(BO3)3Si6O18(OH)4)
igneous
Citrine Quartz
Silicon Dioxide (SiO2) - Ferric Iron impurities
mineral
Granite
Phaneritic Felsic Intrusive Rock (Granite)
Igneous
Diamond
Cubic Carbon (C)
mineral
Sandstone (Quartzose)
Arenite (composed primarily of SiO2)
sedimentary
Smoky Quartz
Silicon Dioxide (SiO2) with aluminum impurities
mineral
Granite
Phaneritic Intrusive Igneous Rock (composed of Quartz, Feldspar, and Mica)
igneous
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral