Chert (Smooth River Pebble)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Category
Browse organic gemstone (not a rock) specimens identified by the Rock Identifier community.
Chert (Smooth River Pebble)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Fossil Coral
Phylum Cnidaria / Rugosa or Tabulata
Banded Chert
Microcrystalline Quartz (SiO2)
Shale
Shale (clay-sized silicate minerals)
Dyed Agate (Tumbled)
Silicon Dioxide (Chalcedony variety, artificially dyed)
Chalcedony Pebble
Silicon Dioxide (SiO2)
Milky Quartz Nodule / Geode precursor
Silicon Dioxide (SiO2)
Lake Superior Agate
Banded Chalcedony / Silicon Dioxide (SiO2)
Red Jasper
Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions
Jasper
Jasper (Silicon Dioxide, SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Quartz (Milky/Common)
Silicon Dioxide (SiO2)
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2)
Banded Agate (Dyed)
SiO2 (Silicon Dioxide / Microcrystalline Quartz)
Chert Pebble
Chert (composed primarily of Microcrystalline Quartz, SiO2)
Limestone
Calcium Carbonate (CaCO3)
Chert (Jasper/Flint variety)
Microcrystalline quartz (SiO2)
Chert (specifically Flint or Novaculite variant)
Chert (Microcrystalline Quartz, SiO2)
Chert (Green Chert)
Microcrystalline silica (SiO2)
Chert (Jasper)
Microcrystalline Quartz (SiO2)
Fossiliferous Limestone (Crinoid stem fragment)
Crinoidea (Phylum Echinodermata) in Calcite matrix
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified wood / Permineralized wood (SiO2)
Limonite-stained Chert
Silicon Dioxide (SiO2) with Hydrated Iron Oxide (FeO(OH)·nH2O)
Crushed Limestone
Sedimentary Calcite/Dolomite Rock (CaCO3)
Rhyolite (Leopard Skin Jasper)
Rhyolite (Silicon Dioxide with impurities)
Tiger Iron
Tiger Iron (Hematite, Red Jasper, and Tiger's Eye)
Serpentine (Serpentinite)
Antigorite, Lizardite, or Chrysotile; (Mg,Fe)3Si2O5(OH)4
Unakite
Epidotized Granite
Fossiliferous Limestone
Fossiliferous Limestone (Sedimentary Rock)
Petrified Wood
Silicified Wood (primarily SiO2)
Chert (variant Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Quartz Geode
Silicon Dioxide (SiO2)
Chert Cobble / Quartzite River Stone
Microcrystalline Quartz (SiO2) / Quartzite
Graphite Schist
C (Carbonaceous Schist)
Pearl
Organic Mineraloid (CaCO3 + Conchiolin)
Moss Agate
Silicon Dioxide (SiO2) with Manganese/Iron Oxide inclusions
Amber (Raw Copal)
Fossilized Plant Resin (Gummite/Succinite)
Chert
Microcrystalline Quartz (SiO2)
Chert (often called Flint or Jasper based on color)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Jasper
Silicon Dioxide (Microcrystalline Quartz, $SiO_2$)
Chert (River Pebble)
Cryptocrystalline Quartz (SiO2)