Rock Identifier

Category

Organic Gemstone (Biogenic)

Browse organic gemstone (biogenic) specimens identified by the Rock Identifier community.

Learn about Organic Gemstone (Biogenic) in the encyclopedia

Jet

Petrified Wood (Silicified Paleoxylon (SiO2)) — fossil

Petrified Wood

Silicified Paleoxylon (SiO2)

Chert (often called Flint in dark varieties) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (often called Flint in dark varieties)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

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

Chert (Flint)

Microcrystalline Quartz (SiO2)

Petrified Wood (Silicified Wood (SiO2)) — mineral

Petrified Wood

Silicified Wood (SiO2)

Polished banded agate (likely picture jasper or petrified wood) (Microcrystalline quartz, SiO₂, with iron-oxide and clay inclusions) — gemstone

Polished banded agate (likely picture jasper or petrified wood)

Microcrystalline quartz, SiO₂, with iron-oxide and clay inclusions

Red Jasper (Quartz (SiO2) with iron oxide inclusions) — sedimentary

Red Jasper

Quartz (SiO2) with iron oxide inclusions

Jasper (Silicon Dioxide (SiO2) with impurities) — sedimentary

Jasper

Silicon Dioxide (SiO2) with impurities

Chert (Yellow/Tan) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Yellow/Tan)

Microcrystalline Quartz (SiO2)

Tumbled brown jasper (likely common jasper or chert) (Microcrystalline quartz, SiO₂, chiefly chalcedony/quartz with iron-oxide impurities) — mineral

Tumbled brown jasper (likely common jasper or chert)

Microcrystalline quartz, SiO₂, chiefly chalcedony/quartz with iron-oxide impurities

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

Chert (Jasper/Chalcedony)

Microcrystalline Quartz (SiO2)

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

Chert (or Chalcedony)

Microcrystalline Quartz (SiO2)

Petrified Wood (Silicified Wood (primarily SiO2)) — metamorphic

Petrified Wood

Silicified Wood (primarily SiO2)

Jasper (Silicon Dioxide (SiO2) with iron oxide impurities) — sedimentary

Jasper

Silicon Dioxide (SiO2) with iron oxide impurities

Yellow Jasper / Chert (Jasper (Silica/Quartz) - SiO2) — sedimentary

Yellow Jasper / Chert

Jasper (Silica/Quartz) - SiO2

Banded Chert (Microcrystalline Quartz (SiO2)) — sedimentary

Banded Chert

Microcrystalline Quartz (SiO2)

Chert (often called Flint or Jasper) (Cryptocrystalline quartz (SiO2)) — sedimentary

Chert (often called Flint or Jasper)

Cryptocrystalline quartz (SiO2)

Chert (White Chert or Flint) (Microcrystalline or cryptocrystalline quartz (SiO2)) — sedimentary

Chert (White Chert or Flint)

Microcrystalline or cryptocrystalline quartz (SiO2)

Chert (specifically Red Chert / Jasper) (Silicon Dioxide (SiO2)) — sedimentary

Chert (specifically Red Chert / Jasper)

Silicon Dioxide (SiO2)

Pearl (Nacre (aragonite, CaCO₃, in an organic conchiolin matrix)) — gemstone

Pearl

Nacre (aragonite, CaCO₃, in an organic conchiolin matrix)

Banded Agate (Dyed) (SiO2 (Silicon Dioxide / Microcrystalline Quartz)) — mineral

Banded Agate (Dyed)

SiO2 (Silicon Dioxide / Microcrystalline Quartz)

Chert (specifically Tan Chert or Flint) (Silicon Dioxide (SiO2)) — sedimentary

Chert (specifically Tan Chert or Flint)

Silicon Dioxide (SiO2)

Petrified Wood (Silicified Wood (SiO2)) — fossil

Petrified Wood

Silicified Wood (SiO2)

Dyed Agate (Tumbled) (Silicon Dioxide (Chalcedony variety, artificially dyed)) — gemstone

Dyed Agate (Tumbled)

Silicon Dioxide (Chalcedony variety, artificially dyed)

Chert (Jasper/Jasperoid) (Chert (chemically precipitated microcrystalline Quartz, SiO2)) — sedimentary

Chert (Jasper/Jasperoid)

Chert (chemically precipitated microcrystalline Quartz, SiO2)

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

Chert (Flint)

Cryptocrystalline Quartz (SiO2)

Baroque cultured pearl necklace (Pearl: nacre composed mainly of aragonite (CaCO₃) and conchiolin) — gemstone

Baroque cultured pearl necklace

Pearl: nacre composed mainly of aragonite (CaCO₃) and conchiolin

Polished moss agate (likely dendritic agate) (Chalcedony, microcrystalline quartz (SiO₂), with inclusions of manganese/iron oxides or hornblende) — gemstone

Polished moss agate (likely dendritic agate)

Chalcedony, microcrystalline quartz (SiO₂), with inclusions of manganese/iron oxides or hornblende

Tumbled amber (Fossilized plant resin; commonly succinite (C10H16O)) — gemstone

Tumbled amber

Fossilized plant resin; commonly succinite (C10H16O)

Moss Agate (Silicon Dioxide (Chalcedony with green mineral inclusions), SiO2) — gemstone

Moss Agate

Silicon Dioxide (Chalcedony with green mineral inclusions), SiO2

Amber (Raw Copal) (Fossilized Plant Resin (Gummite/Succinite)) — mineral

Amber (Raw Copal)

Fossilized Plant Resin (Gummite/Succinite)

Moss Agate (Silicon Dioxide (SiO2) with Manganese/Iron Oxide inclusions) — mineral

Moss Agate

Silicon Dioxide (SiO2) with Manganese/Iron Oxide inclusions

Mookaite Jasper (Silicon Dioxide with Iron Oxide impurities (SiO2)) — mineral

Mookaite Jasper

Silicon Dioxide with Iron Oxide impurities (SiO2)

Petrified Wood (Silicified wood (Quartz/Chalcedony - SiO2)) — mineral

Petrified Wood

Silicified wood (Quartz/Chalcedony - SiO2)

Jasper (Jasper (Cryptocrystalline variety of Quartz, SiO2)) — sedimentary

Jasper

Jasper (Cryptocrystalline variety of Quartz, SiO2)

Yellow-brown translucent mineral fragment, likely citrine or amber (Quartz (SiO₂), if citrine; succinite (fossil resin), if amber) — mineral

Yellow-brown translucent mineral fragment, likely citrine or amber

Quartz (SiO₂), if citrine; succinite (fossil resin), if amber

Amber (Succinite (fossilized resin)) — mineral

Amber

Succinite (fossilized resin)

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

Chert (specifically Flint)

Microcrystalline Quartz (SiO2)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Red Jasper (Silicon Dioxide (SiO2) with Hematite inclusions) — sedimentary

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Petrified Wood (Silicified Wood (SiO2)) — fossil

Petrified Wood

Silicified Wood (SiO2)

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

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Moss Agate (Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxides) — mineral

Moss Agate

Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxides