Placer Gold Nugget
Native Gold (Au)
mineral
Category
Synthetic Or Natural Fiber
Browse synthetic or natural fiber specimens identified by the Rock Identifier community.
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Quartz Pebble (Iron-stained)
Silicon Dioxide (SiO2)
sedimentary
Peacock Ore
Bornite (Cu5FeS4)
mineral
Petrified Wood (Silicified Wood)
Silicified Wood / Silicon Dioxide (SiO2)
metamorphic
Granite
Granite (composed primarily of Quartz SiO2, Feldspar (KAlSi3O8), and Mica)
igneous
Pink Granite
Phaneritic intrusive igneous rock (high Potassium-Feldspar)
igneous
Granite
Granite (Felsic Plutonic Rock)
igneous
Yellow Quartz (Citrine-colored Quartz Pebble)
Silicon Dioxide (SiO2)
mineral
Dyed Agate Slice
Silicon Dioxide (SiO2) with artificial colorants
Mineral (variety of Chalcedony)
Aragonite Star Cluster
Aragonite (Sputnik habit) - CaesarCO3
mineral
Agate
Agate (Silicon Dioxide, SiO2)
mineral
Rough Diamond
Diamond (pure Carbon, C)
mineral
Blue Sapphire
Corundum (Al2O3 with trace Titanium/Iron)
mineral
Amethyst Geode
Amethyst (Silicon Dioxide, SiO2)
mineral
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Magnetite (Iron Ore)
Magnetite (Fe3O4)
mineral
Jasper
Jasper (SiO2 plus impurities)
sedimentary
Amethyst (Quartz Cluster)
Silicon Dioxide (SiO2) with iron impurities
mineral
Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
mineral
Pickled Dragon Eggs (Fictional Interpretation: Purple Agate or Amethyst Geodes)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
mineral
Aqua Aura Quartz
Titanium/Gold-coated Silicon Dioxide (SiO2)
mineral
Blue Glass or Slag Glass
Amorphous Silica (Anthropogenic Glass)
mineral
Green Aventurine
Silicon Dioxide (SiO2) with Fuchsite inclusions (K(Al,Cr)2AlSi3O10(OH)2)
mineral
Granite
Granite (Felsic Plutonic Rock)
igneous
Aventurine
Silicon Dioxide (Quartz with Fuchsite inclusions) - SiO2
metamorphic
Ferruginous Quartz
Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3/FeO(OH)) inclusions
mineral
Blue Sapphire
Corundum (Al2O3 with trace amounts of iron and titanium)
mineral
Green Aventurine
Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)
metamorphic
Heat-Treated Citrine (Amethyst Geode Fragment)
Silicon Dioxide (SiO2) with iron impurities
mineral
Yellow Quartz (Iron-Stained Quartz)
Silicon Dioxide (SiO2) with iron oxide inclusions
mineral
Gold Nugget
Native Gold (Au)
mineral
Amber
Succinate (Organic Fossilized Resin)
mineraloid
Limonite
FeO(OH)·nH2O (Hydrated iron oxide)
mineral
Pink Fluorite
Fluorite (Calcium Fluoride) - CaF2
mineral
Coquina / Fossiliferous Limestone
Coquina (composed primarily of Calcium Carbonate / CaCO3)
sedimentary
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
sedimentary
Amethyst
Silicon dioxide with iron impurities (SiO2:Fe3+)
mineral
Amethyst
Silicon Dioxide (SiO2)
mineral
Limonite (Yellow Ochre)
FeO(OH)·nH2O (Hydrous iron(III) oxide-hydroxide mixture)
Mineral (Iron Ore)
Sandstone Concretion
Arenaceous concretion (primarily SiO2 with Fe2O3 staining)
sedimentary
Howlite (Tumbled)
Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)
mineral
Yellow Quartz (Citrine Quartz or Yellow Chalcedony)
Silicon Dioxide (SiO2)
mineral