Sandstone Chert Concretion
Silica-cemented Concretion (primarily SiO2)
Category
Browse organic (paper and cellulose) specimens identified by the Rock Identifier community.
Sandstone Chert Concretion
Silica-cemented Concretion (primarily SiO2)
Amber with Inclusion
Succiniferous fossil resin (C10H16O)
Moss Agate
Cryptocrystalline Quartz (SiO2 with Manganese or Iron Oxide inclusions)
Peacock Ore
Bornite (Cu5FeS4) or Chalcopyrite (CuFeS2) with iridescent tarnish
Dyed Agate (Tumbled)
Silicon Dioxide (Chalcedony variety, artificially dyed)
Honey calcite (orange calcite)
Calcite, calcium carbonate (CaCO₃)
Amber
Succinite (Resinous fossilized tree sap)
Red Coral (Precious Coral)
Corallium rubrum (Calcium Carbonate, CaCO3)
Amber
Succinite (C10H16O)
Ironstone Concretion
Siderite or Hematite Concretion
Moss Agate
Silicon Dioxide with inclusions (SiO2 + impurities)
Moss Agate
Silicon Dioxide (SiO2) with inclusions
Pickled Dragon Eggs (Fictional Interpretation: Purple Agate or Amethyst Geodes)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Calcite crystal
Calcite (calcium carbonate, CaCO₃)
Amber
Succinite (C10H16O)
Moss Agate / Chalcedony
Silicon Dioxide (SiO2)
Limestone (containing Fossil Mold)
Sedimentary Calcium Carbonate (CaCO3)
Black Limestone with Calcite Veining
Bituminous Limestone (CaCO3 with Organic Carbon inclusions)
Amber
Succinite (specifically Baltic Amber) - Formula: C10H16O (approximate)
Moss Agate
Silicon Dioxide (SiO2) with inclusions
Moss Agate
Silicon Dioxide (SiO2) with inclusions of manganese or iron oxide
Amber
Succinite
Amber
Succinite (fossilized resin)
Polished/tumbled calcite
Calcite (calcium carbonate, CaCO₃)
Green Moss Agate
Silicon Dioxide (SiO2) with inclusions of hornblende or chlorite
Moss Agate
Chalcedony (Silicon Dioxide) with dendritic inclusions (SiO2)
Moss Agate
Silicon Dioxide with inclusions (SiO2 + Fe/Mg/Mn/Chlorite)
Orange Calcite
Calcium Carbonate (CaCO3)
Fossilized Insect in Nodular Matrix
Invertebrata / Insecta fossil in sedimentary concretion
Chert Nodule in Limestone (Flint in Chalk)
SiO2 (Microcrystalline Quartz) in CaCO3 (Calcite)
Sandstone Pebble
Arenite (primarily SiO2)
Tumbled chert or flint pebble
Microcrystalline quartz (SiO₂), likely chert; exact variety uncertain from the image
Petrified Wood
Silicified Wood (SiO2)
Chert (Polished/Tumbled)
Silicon Dioxide (SiO2)
Moss Agate
Silicon Dioxide with inclusions (SiO2 + Mn/Fe oxides)
Black Freshwater Pearls
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
Fossiliferous Chert
Silicon Dioxide (SiO2) with fossil inclusions
Fossilized Shark Tooth (Partial)
Elasmobranchii (fossil tooth fragment)
Moss Agate
Silicon Dioxide (SiO2) with inclusions
Amber
Succinite (specifically for Baltic amber); Chemical formula approximately C10H16O
Amber
Succinite (fossilized tree resin)
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony replacing $SiO_2$)