Rock Identifier

Category

Organic Crystal (Mineraloid)

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

Agatized or Silicified Fossil/Coral, or Jasper (SiO2) — sedimentary

Agatized or Silicified Fossil/Coral, or Jasper

SiO2

Fossiliferous Limestone (Biogenic Sedimentary Rock / CaCO3 with fossil fragments) — sedimentary

Fossiliferous Limestone

Biogenic Sedimentary Rock / CaCO3 with fossil fragments

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

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (Chalcedony/Common Opal) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Chalcedony/Common Opal)

Microcrystalline Quartz (SiO2)

Chert (Flint) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Flint)

Silicon Dioxide (SiO2)

Pyrite (Fool's Gold) Cube (Iron Sulfide (FeS2)) — mineral

Pyrite (Fool's Gold) Cube

Iron Sulfide (FeS2)

Flint (Chert) (Silicon Dioxide (SiO2)) — sedimentary

Flint (Chert)

Silicon Dioxide (SiO2)

Pyrite in Slate (Iron Sulfide (FeS2) in Slate host matrix) — metamorphic

Pyrite in Slate

Iron Sulfide (FeS2) in Slate host matrix

Honey calcite (likely) (Calcite, calcium carbonate (CaCO₃)) — mineral

Honey calcite (likely)

Calcite, calcium carbonate (CaCO₃)

Anthracite Coal (Anthracite (Carbon-based metamorphic rock, 86-97% C)) — metamorphic

Anthracite Coal

Anthracite (Carbon-based metamorphic rock, 86-97% C)

Sandstone with Quartz Crystal Infill (Quartz-cemented quartz arenite) — sedimentary

Sandstone with Quartz Crystal Infill

Quartz-cemented quartz arenite

Coal (Bituminous Coal) (Caustobiolith / Sedimentary Rock) — sedimentary

Coal (Bituminous Coal)

Caustobiolith / Sedimentary Rock

Stromatolite (Fossiliferous Limestone) (Biogenic Limestone (Calcium Carbonate, CaCO3)) — sedimentary

Stromatolite (Fossiliferous Limestone)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Brown translucent mineral fragment, possibly iron-stained quartz or amber (Uncertain; likely quartz (SiO₂) with iron-oxide staining, though amber (fossilized resin) is possible) — mineral

Brown translucent mineral fragment, possibly iron-stained quartz or amber

Uncertain; likely quartz (SiO₂) with iron-oxide staining, though amber (fossilized resin) is possible

Fossiliferous Sedimentary Rock (Sedimentary limestone with invertebrate fossil imprint) — fossil

Fossiliferous Sedimentary Rock

Sedimentary limestone with invertebrate fossil imprint

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

Chert

Chert (Microcrystalline Quartz, SiO2)

Chert (Microcrystalline Quartz (SiO2)) — sedimentary

Chert

Microcrystalline Quartz (SiO2)

Chert (or Chalcedony) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (or Chalcedony)

Microcrystalline Quartz (SiO2)

Chert (White/Gray variety) (Silicon Dioxide (SiO2 / Cryptocrystalline Quartz)) — sedimentary

Chert (White/Gray variety)

Silicon Dioxide (SiO2 / Cryptocrystalline Quartz)

Chert (Flint) (Chert (SiO2)) — sedimentary

Chert (Flint)

Chert (SiO2)

Chert (Nodule) (Chert (Silicon Dioxide, SiO2)) — sedimentary

Chert (Nodule)

Chert (Silicon Dioxide, SiO2)

Amber (Succinite (a fossilized organic resin)) — mineral

Amber

Succinite (a fossilized organic resin)

Moss Agate (SiO2) — mineral

Moss Agate

SiO2

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

Pearl

Calcium Carbonate (Aragonite/Calcite) with Conchiolin

Chrysanthemum Stone (Celestine (SrSO4) or Calcite (CaCO3) in Limestone/Porphyry matrix) — metamorphic

Chrysanthemum Stone

Celestine (SrSO4) or Calcite (CaCO3) in Limestone/Porphyry matrix

Jasper (Microcrystalline Quartz (SiO2)) — sedimentary

Jasper

Microcrystalline Quartz (SiO2)

Chert / Flint (Chert (SiO2)) — sedimentary

Chert / Flint

Chert (SiO2)

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

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Amber (likely Baltic amber) (Fossilized tree resin; chiefly polymerized diterpenoid resin (succinite)) — gemstone

Amber (likely Baltic amber)

Fossilized tree resin; chiefly polymerized diterpenoid resin (succinite)

Banded Limestone (Calcareous sedimentary rock (CaCO3)) — sedimentary

Banded Limestone

Calcareous sedimentary rock (CaCO3)

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

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Chert (Flint) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Flint)

Silicon Dioxide (SiO2)

Jasper Agate (Silicon dioxide (SiO2)) — mineral

Jasper Agate

Silicon dioxide (SiO2)

Chert (Jasper) (Cryptocrystalline Silicon Dioxide (SiO2)) — sedimentary

Chert (Jasper)

Cryptocrystalline Silicon Dioxide (SiO2)

Limestone (Fossiliferous) (Calcium Carbonate (CaCO3) - Bioclastic Limestone) — sedimentary

Limestone (Fossiliferous)

Calcium Carbonate (CaCO3) - Bioclastic Limestone

Chert (Sedimentary Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert

Sedimentary Cryptocrystalline Quartz (SiO2)

Amber (Succinite (fossilized tree resin), C10H16O) — Organic Gemstone

Amber

Succinite (fossilized tree resin), C10H16O

Organic Gemstone

Chert (Flint Nodules) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Flint Nodules)

Silicon Dioxide (SiO2)

Jasper (Jasper (Silicon Dioxide, SiO2)) — sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

Chert Pebble (Microcrystalline Quartz (SiO2)) — sedimentary

Chert Pebble

Microcrystalline Quartz (SiO2)

Chert (Yellow Jasper variant) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Yellow Jasper variant)

Silicon Dioxide (SiO2)

Rough Amber (likely Copal or immature Amber) (Organic gemstone / Succinite (if Baltic)) — mineral

Rough Amber (likely Copal or immature Amber)

Organic gemstone / Succinite (if Baltic)