Basalt Pebble
Basalt
igneous
Category
Synthetic Material (Not A Rock Or Mineral)
Browse synthetic material (not a rock or mineral) specimens identified by the Rock Identifier community.
Learn about Synthetic Material (Not A Rock Or Mineral) in the encyclopedia
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Quartz Geode/Cluster
Quartz (SiO2)
mineral
Milky quartz
Quartz (silicon dioxide, SiO₂)
mineral
Coquina or Fossiliferous Limestone
Fossiliferous Limstone (CaCO3)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Druzy Quartz Geode (Partially Open)
Silicon Dioxide (SiO2) within Sedimentary Host Rock
sedimentary
River Rock (Sandstone or Quartzite)
Clastic Sedimentary Rock / Quartzite
sedimentary
Metal Alloy (Jewelry)
Not a naturally occurring rock or mineral; likely a metal alloy for jewelry. Possible compositions include sterling silver (92.5% silver, 7.5% copper), or other silver/gold alloys.
Man-made Material (jewelry, metal alloy)
Green Slate (Greenstone)
Foliated Metamorphic Rock (rich in Chlorite/Epidote)
metamorphic
Likely serpentine (serpentinite) pebbles
Serpentine-group minerals, chiefly antigorite, lizardite, and/or chrysotile; commonly Mg₃Si₂O₅(OH)₄, sometimes containing magnetite, chromite, and minor carbonate minerals
metamorphic
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Petrified Wood / Fossilized Wood
Silicified Wood (Silicon Dioxide - SiO2)
fossil
Tumbled yellow quartz (likely citrine or iron-stained quartz)
Quartz, SiO₂; yellow color from trace iron or irradiation/heat-related coloration
mineral
Granite
Intrusive Igneous Rock
igneous
Chert (often called Flint or Jasper)
Silicon Dioxide (SiO2)
sedimentary
Chert / Flint
Chert (Silicon Dioxide, SiO2)
sedimentary
Quartz Vein in Schist / Gneiss Metamorphic Matrix
Silicon Dioxide (SiO2) in metamorphic schist host rock
metamorphic
Chert (Flint)
Microcrystalline quartz (SiO2)
sedimentary
Copper Ore / Altered Granodiorite
Cupriferous rock with silicate gangue
mineral
Fossil Coral
Scleractinia or Anthozoa (Fossilized)
fossil
Quartzite River Rock (with Quartz Vein)
Quartzite (SiO2)
metamorphic
Diorite (Salt and Pepper Rock)
Diorite
igneous
Geode or Concretion
Silica-rich Concretion or Unopened Geode (SiO2)
sedimentary
Agate
Silicon Dioxide (Chalcedony), SiO2
sedimentary
Ferruginous Sandstone
Clastic Sedimentary Rock (Sandstone with Iron Oxide cement)
sedimentary
Travertine
Tufa limestone (CaCO3)
sedimentary
Basalt River Stone
Basalt
igneous
Basalt River Stone
Basalt (Aphanitic Mafic Igneous Rock)
igneous
Limestone
Calcareous sedimentary rock (primarily Calcium Carbonate, CaCO3)
sedimentary
Limestone (specifically Grainstone or Micrite)
Calcium Carbonate (CaCO3)
sedimentary
Diabase
Diabase (also known as Dolerite)
igneous
Rounded greenstone pebble
Likely serpentinite or chlorite-rich metamorphic rock; exact identification requires testing
metamorphic
Quartzite
Quartzite (Primary mineral: Quartz, SiO2)
metamorphic
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Porphyry (Porphyritic Basalt / Porphyritic Andesite)
Porphyritic Igneous Rock
igneous
Lava Rock (Scoria)
Scoria (Mafic volcanic rock)
igneous
Pink Granite
Intrusive Felsic Igneous Rock
igneous
Chert (Jasper/Chalcedony)
Microcrystalline Quartz (SiO2)
sedimentary
Weathered rhyolite or felsic volcanic rock
Rhyolite, commonly quartz–alkali feldspar–plagioclase with iron-oxide alteration
igneous
Chert (Jasper variety)
Silicon Dioxide (SiO2)
sedimentary
Sandstone
Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)
Sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary