Rock Identifier

Category

Organic Gemstone (Not A Rock Or Mineral)

Browse organic gemstone (not a rock or mineral) specimens identified by the Rock Identifier community.

Noble Serpentine (Antigorite (Mg3Si2O5(OH)4)) — metamorphic

Noble Serpentine

Antigorite (Mg3Si2O5(OH)4)

Mixed Quartz and Jasper Pebbles (Silicon Dioxide (SiO2)) — Mineral

Mixed Quartz and Jasper Pebbles

Silicon Dioxide (SiO2)

Shale (Fissile Mudstone (primarily composed of phyllosilicate minerals like kaolinite, montmorillonite, and illite)) — sedimentary

Shale

Fissile Mudstone (primarily composed of phyllosilicate minerals like kaolinite, montmorillonite, and illite)

Quartz (likely macrocrystalline variety) (Quartz (SiO₂)) — Mineral

Quartz (likely macrocrystalline variety)

Quartz (SiO₂)

Tiger's Eye (Pseudomorph of Quartz after Crocidolite (SiO2 with inclusions)) — metamorphic

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with inclusions)

Yellow Jasper (Iron-stained Quartz) (Jasper (Silicon Dioxide, SiO2 plus iron oxide impurities)) — sedimentary

Yellow Jasper (Iron-stained Quartz)

Jasper (Silicon Dioxide, SiO2 plus iron oxide impurities)

Sandstone or Quartzite (Arenite (if sedimentary) / Quartzite (if metamorphic)) — Sedimentary or Metamorphic

Sandstone or Quartzite

Arenite (if sedimentary) / Quartzite (if metamorphic)

Sedimentary or Metamorphic

Coral Fossil (Scleractinia) (Scleractinia (Order), primarily CaCO3 (Aragonite or Calcite)) — sedimentary

Coral Fossil (Scleractinia)

Scleractinia (Order), primarily CaCO3 (Aragonite or Calcite)

Chert (Iron-stained) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Banded Gneiss (Gneiss (high-grade metamorphic silicate rock)) — metamorphic

Banded Gneiss

Gneiss (high-grade metamorphic silicate rock)

Quartz (Druzy on Matrix) (Silicon Dioxide (SiO2)) — mineral

Quartz (Druzy on Matrix)

Silicon Dioxide (SiO2)

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

Chert (specifically Gray/Black Chert)

Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)

Biotite Mica (Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)) — mineral

Biotite Mica

Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)

Quartz Geode (Silicon Dioxide (SiO2) within a geode) — mineral

Quartz Geode

Silicon Dioxide (SiO2) within a geode

Black Marble (Recrystallized Calcite (CaCO3)) — metamorphic

Black Marble

Recrystallized Calcite (CaCO3)

Moss Agate (Silicon Dioxide (SiO2) with inclusions) — mineral

Moss Agate

Silicon Dioxide (SiO2) with inclusions

Pyrite in Limestone (Iron Sulfide (FeS2) in Calcium Carbonate (CaCO3)) — mineral

Pyrite in Limestone

Iron Sulfide (FeS2) in Calcium Carbonate (CaCO3)

Sandstone with Concretions / Liesegang Rings (Arenite with iron oxide banding) — sedimentary

Sandstone with Concretions / Liesegang Rings

Arenite with iron oxide banding

Sandstone with Quarzite clasts (Arenite (SiO2 based)) — sedimentary

Sandstone with Quarzite clasts

Arenite (SiO2 based)

Sandstone (Arenite) — sedimentary

Sandstone

Arenite

Banded Sandstone (Arenite (with iron oxide banding)) — sedimentary

Banded Sandstone

Arenite (with iron oxide banding)

Quartz (Milky/Crystalline) (Silicon Dioxide (SiO2)) — mineral

Quartz (Milky/Crystalline)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous) (Arenite (Siliclastic Sedimentary Rock)) — sedimentary

Sandstone (Ferruginous)

Arenite (Siliclastic Sedimentary Rock)

Quartz (Quartz (SiO₂ - Silicon Dioxide)) — Mineral

Quartz

Quartz (SiO₂ - Silicon Dioxide)

Chert (often called Flint or Jasper if reddish) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (often called Flint or Jasper if reddish)

Microcrystalline Quartz (SiO2)

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

Chert (Flint)

Microcrystalline Quartz (SiO2)

Desert Varnish on Sandstone (Ferromanganese coating on Quartz Arenite) — sedimentary

Desert Varnish on Sandstone

Ferromanganese coating on Quartz Arenite

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Pink Opal (Hydrated silicon dioxide (SiO2·nH2O) with inclusions) — mineral

Pink Opal

Hydrated silicon dioxide (SiO2·nH2O) with inclusions

Corundum (Corundum (Al2O3)) — Mineral

Corundum

Corundum (Al2O3)

Petrified Wood (Silicified Wood / Chalcedony (SiO2)) — mineral

Petrified Wood

Silicified Wood / Chalcedony (SiO2)

Blue Chalcedony (Silicon Dioxide (SiO2)) — mineral

Blue Chalcedony

Silicon Dioxide (SiO2)

N/A (Non-Geological Specimen) — N/A

N/A (Non-Geological Specimen)

Green Aventurine (Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)3Si3O10(OH)2)) — metamorphic

Green Aventurine

Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)3Si3O10(OH)2)

Gneiss (Pebble) (Gneiss) — metamorphic

Gneiss (Pebble)

Gneiss

Geode with Quartz and possibly Jasper/Hematite (Quartz (SiO2) and Chalcedony (cryptocrystalline SiO2), possibly stained by iron oxides) — Mineral/Sedimentary Geode

Geode with Quartz and possibly Jasper/Hematite

Quartz (SiO2) and Chalcedony (cryptocrystalline SiO2), possibly stained by iron oxides

Mineral/Sedimentary Geode

Sandstone (with Iron Staining) (Clastic Sedimentary Rock (primarily Quartz, SiO2)) — sedimentary

Sandstone (with Iron Staining)

Clastic Sedimentary Rock (primarily Quartz, SiO2)

Orange Calcite (Calcium Carbonate (CaCO3)) — mineral

Orange Calcite

Calcium Carbonate (CaCO3)

Green Calcite (Calcium Carbonate (CaCO3)) — mineral

Green Calcite

Calcium Carbonate (CaCO3)

Quartz (various varieties) (SiO₂ (Silicon Dioxide)) — Mineral

Quartz (various varieties)

SiO₂ (Silicon Dioxide)

Biotite (Black Mica) (Biotite - K(Mg,Fe)3AlSi3O10(F,OH)2) — mineral

Biotite (Black Mica)

Biotite - K(Mg,Fe)3AlSi3O10(F,OH)2