Petrified Wood
Silicified Wood (primarily SiO2)
Category
Browse organic gemstone (not a rock) specimens identified by the Rock Identifier community.
Petrified Wood
Silicified Wood (primarily SiO2)
Amber
Succinite (approximate formula C10H16O)
Glauconitic Sandstone (Greensand)
Glauconitic quartz wacke or arenite
Fossiliferous Limestone with Brachiopod shell
Calcium carbonate (CaCO3)
Clear Quartz (beads in a bracelet)
Quartz (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Chert (Yellow/Tan variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Fluorite Bracelet (light green beads) and possibly Lavender Jadeite (purple bead)
Fluorite: CaF₂ (Calcium Fluoride); Jadeite: NaAlSi₂O₆ (Sodium Aluminum Silicate)
Amber
Succinite (C10H16O)
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, SiO2)
Orthoceras Fossil Limestone
Orthoceras (extinct Cephalopod fossil) in Matrix
Chert (Field Flint)
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Amber
Succinite
Chert (and/or River Pebble)
Microcrystalline quartz (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Chert with Iron Staining
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified wood (Quartz/Chalcedony/Opal replacing organic matter)
Moss Agate
Silicon Dioxide (SiO2) with Chlorite/Oxide inclusions
Chert (often called Flint)
Chert (Cryptocrystalline Quartz, SiO2)
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, formula SiO2)
Chert / Flint
Silicon Dioxide (SiO2)
Amber
Succinite (Resinite)
Agatized Fossil (Druzy Agate)
Silicon Dioxide (SiO2) replacing organic matter
Chert (Pink Jasper)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Chert (Flint variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (varietal Flint)
Chert (SiO2)
Chert (Flint/Chalcedony)
Microcrystalline Quartz (SiO2)
Chert (often called Flint)
Microcrystalline to cryptocrystalline quartz (SiO2)
Shungite
Shungite (carbon-rich Precambrian mineraloid)
Anthracite Coal
Anthracite (Carbon-rich metamorphic coal)
Pyrite in Shaly Matrix
Iron Sulfide (FeS2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Agate (or Banded Agate)
Agate (a variety of Chalcedony, which is a cryptocrystalline form of Quartz); Chemical Formula: SiO₂ (Silicon Dioxide)
Chert Pebble
Microcrystalline Quartz (SiO2)
Chert (Arrowhead Preform)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Chert (often called Flint in this context)
Silicon Dioxide (SiO2)
Chert (often called Jasper in this color variety)
Microcrystalline Quartz (SiO2)
Quartz
Quartz (Silicon Dioxide, SiO2)