Pink Opal
Hydrated Silica (SiO2·nH2O) with Palygorskite inclusions
Mineraloid
Category
Organic (Biological Specimen)
Browse organic (biological specimen) specimens identified by the Rock Identifier community.
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petoskey Stone
Hexagonaria percarinata (Fossilized Coral)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Bituminous Coal
Organic Sedimentary Rock (composed mostly of carbon with sulfur and hydrogen)
sedimentary
Pink Opal / Peruvian Opal
Hydrated amorphous silicon dioxide (SiO2·nH2O)
Mineral
Pearl (Cultured or Natural)
Aragonite (CaCO3) with Conchiolin
Organic Mineraloid
Amber (Cherry Amber)
Succinite (C10H16O)
Organic Gemstone
Popcorn
Zea mays everta (P. Wilson) (Botanical name for the corn variety)
Organic/Biogenic
Amber
Succinite (a specific high-quality amber from the Baltic)
Organic Mineraloid
Amber
Succinite (Fossilized Resin C10H16O)
Organic Mineraloid
Amber (Burmite)
Fossilized tree resin (Succinite variant)
Organic mineraloid
Amber
Succinite (fossilized resin)
Organic Mineraloid
Ambergris
Ambrein (C30H52O Derivative)
Organic (Zoogenic)
Amber (Butterscotch/Egg Yolk Variety)
Succinite (Approx. C10H16O)
Organic Gemstone
Baroque Pearl
Calcium Carbonate (Aragonite or Calcite) and Conchiolin
Organic Gemstone
Bivalve Shell (Fossil or Contemporary)
Class Bivalvie (various genera and species of clams, cockles, etc.)
Sedimentary (Biogenic sediment or biological remain)
Amber
Succinite (Formula: C10H16O)
Organic Mineraloid
Pyrite
Pyrite (Iron Disulfide), FeS2
Mineral
Cherry Creek Jasper (also known as Red Creek Jasper or Cherry Creek Agate)
Jasper, microcrystalline quartz (SiO₂)
Sedimentary Rock
Coal (specifically Bituminous or Anthracite)
Organic sedimentary rock; primarily Carbon (C) with varying H, S, O, N
sedimentary
Shale or Mudstone (Based on appearance)
Shale (fine-grained, laminated fissile sedimentary rock) / Mudstone (fine-grained, non-fissile sedimentary rock)
Sedimentary
Petrified Wood
Silicified wood, primarily composed of Quartz (SiO2)
Mineral, often found in sedimentary deposits
Coral (Precious Coral)
Corallium rubrum (Red Coral), Paracorallium japonicum (Momo Coral), Pleurocorallium elatius (Sardinian Coral), various other species within the Corallidae family. Chemically, it's primarily Calcium Carbonate (CaCO 3 ).
Mineral, Organic Gemstone
Baltic Amber (Butterscotch or Egg Yolk Variety)
Succinite (C10H16O)
Organic Gemstone (Mineraloid)
Shale
Shale (clastic sedimentary rock)
Sedimentary
Baltic Amber (Butterscotch variety)
Succinite
Organic Gemstone/Mineraloid
Banded Chert / Banded Jasper (likely a variety of Chert/Chalcedony)
Chert (microcrystalline quartz)
Metamorphic Rock
Pyrite
Pyrite (Iron sulfide, FeS₂)
mineral
Amber (Simulated/Faturan Style)
Resin mix (Likely Phenolic/Celluloid if synthetic, Succinite if natural)
Organic Gemstone (not a mineral)
Ambergris
Ambra grisea (Metabolic byproduct)
Organic (Geological relative)
Ambergris
Ambrein-rich Calculus
Organic (Pseudo-geological)
Brachiopod Fossil (Spiriferid)
Phylum Brachiopoda, Order Spiriferida (CaCO3 - Calcium Carbonate)
sedimentary (fossilized organic remains)
Brachiopod Fossil (Spiriferid)
Order Spiriferida (Phylum Brachiopoda); mineralized as Calcite (CaCO3) or Chert (SiO2)
sedimentary (fossilized organic remain)
Anthracite Coal
Anthracite (Carbon-based organic sedimentary rock exposed to metamorphic heat/pressure; Chemical composition is approximately 86%–98% Carbon)
metamorphic
Chert (variously identified as Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Pumice
Vesicular volcanic glass (primarily SiO2 with Al2O3)
Igneous
Limestone (Cliff Formation)
Limestone (predominantly CaCO3 as calcite)
Sedimentary
Fossilized Coral (Petoskey Stone / Favosites)
Favosites (extinct genus of tabulate coral)
sedimentary
Sandstone (with potential trace fossils)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Fossiliferous Limestone
Biogenic Calcium Carbonate (CaCO3)
sedimentary
Fossiliferous Limestone
Calcium Carbonate (CaCO3) with Bioclastic Inclusions
sedimentary