Unidentified Dark Mineral or Rock
Indeterminate (Likely Silicon Dioxide or Carbon-based)
Category
Browse mineraloid (organic) specimens identified by the Rock Identifier community.
Unidentified Dark Mineral or Rock
Indeterminate (Likely Silicon Dioxide or Carbon-based)
Ironstone Concretion (Boxwork)
Siderite-Limonite Concretion (FeO(OH)·nH2O)
Amber
Succinite (fossilized tree resin)
Moss Agate
Silicon Dioxide with inclusions (SiO2 + Mn/Fe/Chlorite)
Amber
Succinite (Resin)
Amber
Succinite (approximate formula C10H16O)
Petrified Wood
Silicified Wood (SiO2)
Amber
Succinite (C10H16O)
Amber
Succinite (approximate formula C10H16O)
Petrified Wood
Silicified Wood (primarily SiO2)
Agate (Moss or Dendritic Agate)
Chalcedony (Silicon Dioxide, SiO2)
Amber
Succinite / Fossilized Resin (C10H16O)
Garden Quartz
Included Quartz (SiO2 with accessory minerals such as Chlorite, Hematite, or Feldspar)
Amber
Organic gemstone (Succinite is common if from the Baltic)
Glauconite
Glauconite (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2
Limestone Pebble
Sedimentary Rock (Calcite, CaCO3)
Chert
Chert (Microcrystalline Quartz, SiO2)
Banded calcite (travertine or calcite-rich carbonate)
Calcite, CaCO₃; likely banded travertine or recrystallized limestone
Pearls
Pearl: biomineralized aragonite (CaCO₃) and conchiolin
Flint / Chert Nodule
Microcrystalline quartz (SiO2)
Moss Agate
Silicon Dioxide with inclusions (SiO2)
Amber
Succinite (Fossilized Resin)
Amber
Succinited (fossilized tree resin)
Petrified Wood
Silicified Wood (SiO2)
Dendritic Agate (Tree Agate)
Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions
Amber (Copal)
Succinite (fossilized resin)
Petrified Wood
Silicified Wood (SiO2)
Agate (Moss or Green Agate)
Silicon Dioxide (SiO2)
Limestone (River Pebble)
Calcium Carbonate (CaCO3)
Amber
Succinite (approximate formula C10H16O)
Dendritic Agate
Silicon Dioxide with Manganese/Iron oxide inclusions (SiO2)
Green Moss Agate
Agate (Silicon Dioxide, SiO2) with inclusions of hornblende or chlorite
Moss Agate
Chalcedony (Silicon Dioxide, SiO2) with inclusions
Fossilized Bivalve Shell
Class Bivalvia (fossilized)
Enrolled Trilobite Fossil
Phylum Arthropoda, Class Trilobita (likely Calymene or Flexicalymene)
Fossil Shell (Brachiopod or Mollusk)
Phylum Brachiopoda or Class Bivalvia (e.g., Mucrospirifer or similar genus)
Amber
Succinite (fossilized resin, C10H16O)
Mother of Pearl (Nacre)
Nacre (Aragonite/Conchiolin), CaCO3 + Organic Polymers
Opalite
Synthetic Opalite Glass
Slag Glass
Amorphous Silica Glass (with metal oxide inclusions)
Chalcedony (or a variety of Chalcedony, likely Agate or Jasper)
Chalcedony (SiO₂)
Synthetic Resin (Artificial Specimen)
Polyurethane or Polyester Resin