Black Obsidian
Volcanic Glass (SiO2 + impurities)
igneous
Category
Organic (Non Rock)
Browse organic (non rock) specimens identified by the Rock Identifier community.
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Graphite-rich metamorphic rock (graphitic schist)
Graphitic schist; chiefly graphite (C), quartz (SiO₂), and mica minerals
metamorphic
Quartzite
Quartzite (composed primarily of SiO2)
metamorphic
Banded gneiss pebble
Gneiss, typically quartz–feldspar–mica; exact mineral composition requires testing
metamorphic
Fossil Snail Shell
Gastropoda fossil
fossil
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Fossilized Shell Fragment
Invertebrate fossil / Brachiopod or Mollusk shell fragment (Calcium carbonate, CaCO3)
fossil
Greenstone / Glauconitic Siltstone
Metabasalt or Glauconite-rich Sedimentary Rock
metamorphic or sedimentary
Chert Pebble
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Pink Quartzite
Quartzite (SiO2) with trace Iron Oxides
metamorphic
Fossilized Shark Tooth
Chondrichthyes (class)
fossil
Black Obsidian
Volcanic Glass (Amorphous SiO2 with trace impurities)
igneous
Quartzite
Metamorphic Quartz Rock (SiO2)
metamorphic
Quartzite
Metamorphic Quartz Rock (SiO2)
metamorphic
Basalt
Basalt (Igneous Volcanic Rock)
igneous
Quartzite pebble
Metamorphic rock (mainly SiO2)
metamorphic
Basalt
Basalt (Mafic Volcanic Rock)
igneous
Petrified Wood
Silicified wood (SiO2)
fossil
Shark Tooth Fossil Matrix
Carcharocles / Otodus species embedded in sedimentary matrix
fossil
Quartzite / Sandstone / Chert Mix
Silicon Dioxide (SiO2)
sedimentary and metamorphic
Chert Concretion
Sedimentary Cryptocrystalline Quartz (SiO2)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Granite
Granite (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Quartzite River Rock
Metamorphic Quartzite (primarily SiO2)
metamorphic
Zebra Limestone
Calcareous sedimentary rock (CaCO3)
sedimentary
Fossiliferous Sandstone
Sedimentary rock containing invertebrate fossils
fossil
Amber beads
Amber, fossilized plant resin; largely polymerized terpenoid resin (not a mineral)
gemstone
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
igneous
Quartz-rich metamorphic rock, likely quartzite
Quartzite (mostly crystalline SiO₂), possibly quartz-rich schist or vein quartz
metamorphic
Limestone or Sandstone Cobble
Sedimentary rock (Calcium carbonate or Quartz based)
sedimentary
Moldavite
Tektite (Impact Glass), ~80% SiO2 + Al2O3
tektite
Barite
Barium sulfate (BaSO4)
mineral
Quartzite
Metamorphosed Quartz Sandstone (SiO2)
metamorphic
Pink granite or granitic gneiss pebble
Granitic rock, mainly quartz, feldspar, and mica; possibly weathered gneiss
igneous
Quartzite Pebble
Metamorphic rock predominantly composed of Quartz (SiO2)
metamorphic
Weathered limestone or calcareous sandstone
Calcitic carbonate rock, likely limestone (CaCO₃), possibly slightly dolomitic
sedimentary
Basalt (tumbled/river-worn)
Mafic volcanic rock (primarily plagioclase feldspar and pyroxene)
igneous
Amber
Succinite (Fossilized Resin C10H16O)
Organic Mineraloid
Limestone with Calcite Veining
Sedimentary Rock (Calcium Carbonate, CaCO3)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Red Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Ironstone Concretion (Moqui Marble / Boji Stone)
Sedimentary Iron Oxide Concretion (Fe2O3 / FeO(OH))
sedimentary