Rock Identifier

Category

Organic Crystal (Mineraloid)

Browse organic crystal (mineraloid) specimens identified by the Rock Identifier community.

Bituminous Coal (with Anthracite or Vitrinite inclusion) (Organic-rich Sedimentary Rock (Carboniferous classification)) — sedimentary

Bituminous Coal (with Anthracite or Vitrinite inclusion)

Organic-rich Sedimentary Rock (Carboniferous classification)

Coal (Coal (Sedimentary Rock / Organic Rock)) — sedimentary

Coal

Coal (Sedimentary Rock / Organic Rock)

Bituminous Coal (Organic Sedimentary Rock (Carbon-based)) — sedimentary

Bituminous Coal

Organic Sedimentary Rock (Carbon-based)

Pyrite (Pseudomorph) (Iron Sulfide (FeS2)) — mineral

Pyrite (Pseudomorph)

Iron Sulfide (FeS2)

Dark flint or chert fragment (Microcrystalline quartz (SiO₂), likely chert/flint) — sedimentary

Dark flint or chert fragment

Microcrystalline quartz (SiO₂), likely chert/flint

Freshwater Pearl (Aragonite / Biogenic Calcium Carbonate (CaCO3)) — mineral

Freshwater Pearl

Aragonite / Biogenic Calcium Carbonate (CaCO3)

Chert Nodules in Limestone (Cryptocrystalline Quartz (SiO2) within Calcium Carbonate (CaCO3)) — sedimentary

Chert Nodules in Limestone

Cryptocrystalline Quartz (SiO2) within Calcium Carbonate (CaCO3)

Red Coral (Sponge Coral / Apple Coral) (Corallium rubrum (calcium carbonate / organic gem)) — gemstone

Red Coral (Sponge Coral / Apple Coral)

Corallium rubrum (calcium carbonate / organic gem)

Fossilized Shark Tooth (Chondrichthyes (class)) — fossil

Fossilized Shark Tooth

Chondrichthyes (class)

Chert (specifically Gray/Black Chert) (Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)) — sedimentary

Chert (specifically Gray/Black Chert)

Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)

Kidney Stone (Calcium Oxalate (CaC2O4), Uric Acid, or Struvite) — mineral

Kidney Stone

Calcium Oxalate (CaC2O4), Uric Acid, or Struvite

Aragonite (Star Cluster or Twinned variety) (Aragonite (Calcium Carbonate, CaCO3)) — mineral

Aragonite (Star Cluster or Twinned variety)

Aragonite (Calcium Carbonate, CaCO3)

Sand Tiger Shark Tooth (Carcharias taurus) — fossil

Sand Tiger Shark Tooth

Carcharias taurus

Coal (most likely Bituminous or Anthracite) (Coal (organic sedimentary rock)) — Sedimentary

Coal (most likely Bituminous or Anthracite)

Coal (organic sedimentary rock)

Freshwater Pearl (Calcium Carbonate (CaCO3) - Aragonite/Calcite organic composite) — gemstone

Freshwater Pearl

Calcium Carbonate (CaCO3) - Aragonite/Calcite organic composite

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Amber (Succinite (C10H16O)) — mineral

Amber

Succinite (C10H16O)

Amber (Succinite / Fossilized Resin (C10H16O)) — fossil

Amber

Succinite / Fossilized Resin (C10H16O)

Fossilized Wood / Petrified Wood (Petrified Wood (Silicified Flora)) — fossil

Fossilized Wood / Petrified Wood

Petrified Wood (Silicified Flora)

Pearl (Calcium Carbonate (Aragonite/Calcite) with Conchiolin, CaCO3) — gemstone

Pearl

Calcium Carbonate (Aragonite/Calcite) with Conchiolin, CaCO3

Chert Pebble (Chert (SiO2)) — sedimentary

Chert Pebble

Chert (SiO2)

Chert (Flint) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Flint)

Microcrystalline Quartz (SiO2)

Dinosaur Claw Fossil (Fossilized Theropod Claw (Vertebrate Palaeontological Specimen)) — fossil

Dinosaur Claw Fossil

Fossilized Theropod Claw (Vertebrate Palaeontological Specimen)

Chert Concretion (Microcrystalline Quartz (SiO2) in Carbonate Matrix) — sedimentary

Chert Concretion

Microcrystalline Quartz (SiO2) in Carbonate Matrix

Pearl (Calcium carbonate (CaCO3) as Aragonite or Calcite) — mineral

Pearl

Calcium carbonate (CaCO3) as Aragonite or Calcite

Jasper (Microcrystalline quartz (SiO2)) — sedimentary

Jasper

Microcrystalline quartz (SiO2)

Petrified Wood (Silicified Wood (SiO2 permineralization)) — fossil

Petrified Wood

Silicified Wood (SiO2 permineralization)

Likely bituminous coal (Coal, predominantly carbon-rich organic matter with variable maceral and mineral content) — sedimentary

Likely bituminous coal

Coal, predominantly carbon-rich organic matter with variable maceral and mineral content

Paper (Cellulose) (Cellulose (C6H10O5)n) — Organic (Anthropogenic)

Paper (Cellulose)

Cellulose (C6H10O5)n

Organic (Anthropogenic)

Shungite (Non-crystalline carbon (Fullerenes)) — metamorphic

Shungite

Non-crystalline carbon (Fullerenes)

Petrified Wood (Silicified Wood (SiO2 - Quartz/Chalcendony replacing organic matter)) — sedimentary

Petrified Wood

Silicified Wood (SiO2 - Quartz/Chalcendony replacing organic matter)

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Amber (Succinate (Fossilized Resin)) — mineral

Amber

Succinate (Fossilized Resin)

Agatized Fossil Coral (Agatized Anthozoa) — fossil

Agatized Fossil Coral

Agatized Anthozoa

Petrified Wood (Silicon Dioxide (SiO2)) — fossil

Petrified Wood

Silicon Dioxide (SiO2)

Fossilized Shark Tooth (Megalodon or Carcharocles species fragment) (Otodus megalodon / Carcharocles spp. (Apatite / Calcium Phosphate)) — fossil

Fossilized Shark Tooth (Megalodon or Carcharocles species fragment)

Otodus megalodon / Carcharocles spp. (Apatite / Calcium Phosphate)

Petrified Wood (Petrified Wood (Silicified Wood)) — fossil

Petrified Wood

Petrified Wood (Silicified Wood)

Chert (often called Flint) (Chert (Microcrystalline Silicon Dioxide, SiO2)) — sedimentary

Chert (often called Flint)

Chert (Microcrystalline Silicon Dioxide, SiO2)

Graphite (Carbon (C)) — mineral

Graphite

Carbon (C)

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Chert (Flint) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Flint)

Microcrystalline Quartz (SiO2)

Shale (Laminated Fissile Pelite) — sedimentary

Shale

Laminated Fissile Pelite