Obsidian
Volcanic Glass (SiO2 with impurities)
igneous
Category
Organic (Non Rock)
Browse organic (non rock) specimens identified by the Rock Identifier community.
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Red coral chip bracelet
Corallium spp.; skeleton composed primarily of calcium carbonate (aragonite)
gemstone
Likely bituminous coal
Coal, predominantly carbon-rich organic matter; exact rank cannot be confirmed visually
sedimentary
Petrified wood
Silicified wood, commonly quartz (SiO₂) replacing woody tissue
fossil
Amber (likely a small rough amber piece)
Fossilized plant resin; amber is an organic mineraloid, not a crystalline mineral
gemstone
Fossiliferous Limestone
Fossiliferous Limestone (CaCO3)
sedimentary
Baltic Amber
Succinite (Polmerized conifer resin)
mineraloid
Coal (Anthracite or Bituminous)
Carbonaceous sedimentary rock (Carbon)
sedimentary
Sandstone with Brachiopod Mold Fossil
Sedimentary rock (Sandstone) with indeterminate Brachiopod mold
fossil
Fossil bone or tooth fragment
Indeterminate fossilized vertebrate bone/tooth; taxonomic identification is not possible from this blurred image
fossil
Quartz vein in host rock
Milky quartz (SiO₂) with likely metamorphic country rock, possibly gneiss or schist
metamorphic
Obsidian
Volcanic Glass (Mainly SiO2)
igneous
Fossilized Shark Tooth
Chondrichthyes teeth
fossil
Quartzite
Metamorphic Quartz Rock (SiO2)
metamorphic
Quartzite
Metamorphic Quartz Rock (SiO2)
metamorphic
Quartzite
Metamorphic Quartz Rock (SiO2)
metamorphic
Quartzite
Metamorphic Quartz Rock (SiO2)
metamorphic
Opalite
Synthetic Opalised Glass
Mineral (Synthetic / Man-made)
Coal
Bituminous Coal (organic sedimentary rock)
sedimentary
Bituminous Coal
Bituminous coal (Organic Sedimentary Rock)
sedimentary
Bituminous Coal
Organic Sedimentary Rock (Carbon-based)
sedimentary
Bituminous Coal
Organic Sedimentary Rock (Carbon-based)
sedimentary
Amber
Succinite (a specific common type) or Fossilized Tree Resin (C10H16O)
Mineraloid
Quartzite
Metamorphic Quartz Rock (SiO2)
metamorphic
Polished operculum (“Shiva eye” shell)
Calcium-carbonate shell operculum, commonly from a turban snail (family Turbinidae); not a mineral specimen
fossil
Limestone and Sandstone Assortment
Sedimentary Rock Assemblage
sedimentary
Amber
Succinite (specifically for Baltic amber); C10H16O (Variable organic compound)
mineral
Quartzite River Rock
Metamorphic Rock (Quartzite)
metamorphic
Shale or Mudstone River Pebble
Argillaceous sedimentary rock
sedimentary
Fossilized Bone
Vertebrate Fossil (Biogenic sediment)
fossil
Fossiliferous Limestone (Shell Fragment)
Biogenic Limestone (Calcium Carbonate / CaCO3)
sedimentary
Dark, rounded rock (possibly basalt)
Undetermined; basalt is a tentative visual identification
igneous
Sandstone
Sandstone (Siliciclastic Sedimentary Rock)
sedimentary
Coprolite
Fossilized feces
fossil
Anthracite Coal
Anthracite (Carbon-rich metamorphic coal)
metamorphic
Jasper
Silicon dioxide (Microcrystalline quartz, SiO2)
sedimentary
Sandstone
Arenite (SiO2 composed primarily of quartz)
sedimentary
Chert
Silicon dioxide (SiO2)
Sedimentary
Limestone (Karst formation)
Calcium Carbonate (CaCO3)
sedimentary
Fossilized Bone
Petrified Bone / Biogenic Sedimentary
fossil
Obsidian
Volcanic Glass (Amorphous SiO2)
igneous
Amber
Succinite (fossilized tree resin, C10H16O)
fossil