Quartzite Pebble (River Rock)
Quartzite (primarily SiO2)
metamorphic
Category
Man Made Alloy (Metallic)
Browse man made alloy (metallic) specimens identified by the Rock Identifier community.
Porphyritic Rhyolite (Red Porp)
Porphyritic Rhyolite (Felsic volcanic rock)
igneous
Chert (Holey Stone)
Microcrystalline Quartz (SiO2)
sedimentary
Granitic Gneiss
Gneiss (High-grade Metamorphic Rock)
metamorphic
Quartz (Variety: Citrine or Tumbled Chalcedony)
Silicon Dioxide (SiO2)
mineral
Granite (weathered/river-tumbled)
Granite (Plutonic Igneous Rock)
Igneous Rock
Grooved Maun Ball (Maul/Hammerstone-like Concretion)
Calcareous/Ferruginous Concretion in Sandstone Matrix
sedimentary
Sandstone
Arenite (general term for sandstone)
Sedimentary Rock
Milky Quartz Pebble (Iron-stained)
Silicon Dioxide (SiO2)
mineral
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Citrine Quartz
Silicon Dioxide (SiO2) with iron impurities
mineral
Chert / Flint
Cryptocrystalline Quartz (SiO2)
sedimentary
Jasper (Red Jasper with Quartz veins)
Jasper (Silicon Dioxide, SiO2)
sedimentary
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Shale
Fissile mudrock (composed of clay-sized particles and detrital grains)
sedimentary
Sandstone
Arenite (primarily Quartz, SiO2)
sedimentary
Chert (Nodule)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
African Turquoise
Teal Jasper (Macro-crystalline Quartz/Sio2 + Inclusions of Copper, Iron, and Manganese)
sedimentary
Diabase (also known as Dolerite)
Diabase / Microgabbro
igneous
Green Fluorite
Calcium Fluoride (CaF2)
mineral
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
igneous
Emerald
Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities
mineral
Quartz (Clear / Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Amber
Succinite (Fossilized Tree Resin)
mineral
Serpentine
Serpentinite (a rock composed primarily of serpentine minerals like antigorite, chrysotile, and lizardite; general formula (Mg, Fe)3Si2O5(OH)4)
metamorphic
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
mineral
Serpentinite
Serpentinite ((Mg,Fe,Ni,Al)3Si2O5(OH)4)
metamorphic
Peridotite (Olivine/Peridot)
Peridotite: (Mg,Fe)2SiO4 (Olivine-rich ultramafic rock)
igneous
Pink Granite
Phaneritic Felsic Intrusive Igneous Rock
igneous
Moonstone
Orthoclase Feldspar (KAlSi3O8)
Mineral
Quartzite
Quartzite (primarily SiO2)
metamorphic
Red Quartzite Cobble
Quartzite (primarily SiO2)
metamorphic
Quartz (River Pebble)
Silicon Dioxide (SiO2)
Mineral
Amethyst
Amethyst (Silicon Dioxide, SiO2)
mineral
Chert (and its variety Flint)
Silicon Dioxide (SiO2) - Microcrystalline or cryptocrystalline Quartz
sedimentary
Prehnite
Prehnite (Ca2Al2Si3O10(OH)2)
mineral
Granite with Epidote
Granite, containing quartz, feldspar, and epidote
Igneous
Agate Nodule / Weathered Chert
SiO2 (Silicon Dioxide - Microcrystalline Quartz)
Sedimentary / Mineral
Granite (tumbled pebble)
Granite (Plutonic Igneous Rock)
Igneous Rock
Red Jasper or Chert
Jasper (SiO2, a variety of chalcedony with iron oxide impurities), Chert (SiO2)
sedimentary
Granite
Granite (a plutonic igneous rock)
Igneous