Pearl
Aragonite / Calcium Carbonate (CaCO3)
Category
Browse organic gemstone (not a rock) specimens identified by the Rock Identifier community.
Pearl
Aragonite / Calcium Carbonate (CaCO3)
Chert (Mudstone)
Microcrystalline Quartz (SiO2)
Amber
Succinite
Manganese Dendrite on Siltstone
Manganese Oxide (pyrolusite or psilomelane) Dendrites
Chert (Yellow or Brown Jasper)
Microcrystalline Quartz (SiO2)
Chalcedony Geode
Silicon Dioxide (SiO2)
Chert Pebble Map
Microcrystalline Quartz (SiO2)
Sandstone with Iron Staining
Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)
Moss Agate
Chalcedony (Silicon Dioxide - SiO2) with inclusions
Chert (Field Stone)
Silicon Dioxide (SiO2)
Chert (and Jasper)
Microcrystalline Quartz (SiO2)
Chert (Jasper/Quartzite variety)
Microcrystalline Silica (SiO2)
Chert (and Flint variant)
Chert (SiO2)
Chert (Flint nodule)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Amber
Fossilized Tree Resin (Generic formula roughly C10H16O)
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert
Cryptocrystalline Quartz (SiO2)
Chert (Nodule)
Microcrystalline quartz (SiO2)
Amber
Succinite (Fossilized Tree Resin)
Fluorite
Fluorite (CaF2)
Chert (Iron-stained or Dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Jasper
Silicon dioxide (SiO2)
Jasper
Silicon Dioxide (SiO2) with impurities
Chert (Jasper transition)
Microcrystalline Quartz (SiO2)
Pearl
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
Chert (Jasper/Agate)
Silicon Dioxide (SiO2)
Red Jasper
Silicon Dioxide (SiO2) with Iron inclusions
Chert (Black Chert / Flint)
Silicon Dioxide (SiO2)
Amber
Succinite (a variety of fossilized tree resin); chemical formula appx. C10H16O
Chert
Chert (Microcrystalline Quartz, SiO2)
Fossiliferous Limestone
Biogenic Sedimentary Rock (CaCO3)
Limestone
Calcium Carbonate (CaCO3)
Shale or Siltstone
Sedimentary Clastic Rock (Variable mineral composition including quartz and clay minerals)
Chert (Flint)
Silicon Dioxide (SiO2)
Chert (with Quartz Druzy)
Microcrystalline Silica (SiO2)
Limestone with Stylolites
Calcareous sedimentary rock (CaCO3)
Shark Tooth Fossil
Vertebrate fossilized tooth
Chert (specifically Flint or Jasper variant)
Microcrystalline Quartz (SiO2)
Chert (Iron-stained)
Microcrystalline silica (SiO2) with trace Iron oxide (Fe2O3)
Concretion
Septarian or Siderite Concretion
Limestone (River Pebble)
Calcium Carbonate (CaCO3)