Limonite (Iron Ore)
Limonite (Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O)
Category
Browse organic mineraloid specimens identified by the Rock Identifier community.
Limonite (Iron Ore)
Limonite (Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O)
Travertine
Calcareous Tufa / Travertine (CaCO3)
Pearl
Aragonite / Calcium Carbonate (CaCO3)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Amber with dark mineral/organic inclusions
Fossilized plant resin (amber; chiefly polymerized diterpenoid resin)
Tumbled amber
Amber (fossilized plant resin; commonly succinite, C10H16O)
Tumbled brown quartz/chert pebble
Microcrystalline quartz (SiO₂), possibly chert or jasper
Amber
Succinite (Fossilized Tree Resin)
Botiroidal Chalcedony or Silicified Fossil Coral
Silicon Dioxide (SiO2) - Chalcedony / Scleractinia (if fossilized)
Mixed Gemstone and Mineral Collection
Silicon Dioxide (SiO2) based minerals and others
Moss Agate
Silicon Dioxide (SiO2) with inclusions
Ironstone Concretion (Limonite/Goethite)
Iron oxide concretion (contains FeO(OH)·nH2O)
Moss Agate
Chalcedony (Silicon Dioxide, SiO2) with inclusions
Tree Agate
Dendritic Agate (Silicon Dioxide, SiO2 with chlorite inclusions)
Moss Agate
Chalcedony (SiO2) with inclusions of manganese or iron oxides
Petrified Wood
Silicified Wood (SiO2)
Moss Agate
Silicon Dioxide (SiO2) with Chlorite/Oxide inclusions
Petrified Wood
Silicified Wood (SiO2)
Limestone (Tufa/Travertine)
Sedimentary Calcium Carbonate (CaCO3)
Concretion
Septarian Concretion (Fragmentary)
Amber (Rough Baltics/Beach Specimen)
Succinicum (Organic Gemstone - Fossilized Resin)
Chert Nodules or Concretion
Cryptocrystalline Quartz (SiO2)
Chert (containing Fossil Mold)
Silicon dioxide (SiO2)
Amber
Succinates (fossilized tree resin), approximately C10H16O
Fossiliferous Limestone
Biogenic Limestone (CaCO3 with fossil fragments)
Fossiliferous Limestone
Biomicrite / Limestone with fossils
Green Fluorite
Fluorite (Calcium Fluoride, CaF2)
Amber
Fossilized Tree Resin (C10H16O)
Rounded brown sandstone or weathered river cobble
Likely quartz-rich sandstone; exact identification requires a fresh surface and tests
Sandstone with Iron Oxide Concretion
Arenite with Hematite/Goethite Concretion
Amber
Fossilized Tree Resin
Amber
Succinite (Fossilized Tree Resin, C10H16O)
Amber
Succinite (C10H16O)
Sandstone Concretion
Arenaceous concretion (primarily SiO2 with Fe2O3 staining)
Calligraphy Stone
Mariam Jasper (Fossiliferous Limestone with Hematite and Iron)
Black Pearl (Tahitian-style Cultured Pearl)
Calcium Carbonate (Aragonite) with Conchiolin (CaCO3)
Green Moss Agate / Jasper
Silicon Dioxide (SiO2) - Microcrystalline Quartz with Iron and Manganese inclusions
Amber
Succinite (C10H16O)
Shale
Shale (comprised mostly of clay minerals and quartz)
Amber
Succinite (specifically for Baltic amber); chemical formula approx. C10H16O
Chert (Arrowhead Preform)
Silicon Dioxide (SiO2) - Microcrystalline Quartz