Anthracite Coal
Anthracite (Carbon-rich metamorphic coal)
metamorphic
Category
Organic Specimen (Fossil)
Browse organic specimen (fossil) specimens identified by the Rock Identifier community.
Pink Opal
Hydrated Silica (SiO2·nH2O) with Palygorskite inclusions
Mineraloid
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Opal
Hydrous silicon dioxide (SiO2·nH2O)
mineral
Sandstone
Sandstone (composed primarily of sand-sized minerals or rock grains)
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
Amber
Succinite (formula varies, primarily C10H16O)
Mineraloid (Organic)
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
Organic Mineraloid
Amber
Succinite (fossilized resin)
Organic Mineraloid
Amber
Succinite (C10H16O)
Organic Mineraloid
Ambergris
Ambrein (C30H52O Derivative)
Organic (Zoogenic)
Amber
Succinite
Organic (Mineraloid)
Amber (Butterscotch/Egg Yolk Variety)
Succinite (Approx. C10H16O)
Organic Gemstone
Baroque Pearl
Calcium Carbonate (Aragonite or Calcite) and Conchiolin
Organic Gemstone
Sandstone
Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)
Sedimentary
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
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)
Baltic Amber (Butterscotch variety)
Succinite
Organic Gemstone/Mineraloid
Banded Chert / Banded Jasper (likely a variety of Chert/Chalcedony)
Chert (microcrystalline quartz)
Metamorphic Rock
French Bulldog (Blue Variety)
Canis lupus familiaris
Organic (Biological Organism)
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)
Iron Slag
Vitreous glassy waste (Fe-Si-Al-Ca compounds)
Mineral byproduct (anthropogenic / techno-fossil)
Sandstone (with potentially metamorphic or basaltic bands)
Arenite / Lithic Wacke
sedimentary
Ambergris
Ambrein (C30H52O)
mineraloid / organic geological substance
Anthracite Coal
Anthracite (Carbon-based organic sedimentary rock exposed to metamorphic heat/pressure; Chemical composition is approximately 86%–98% Carbon)
metamorphic
Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
Organic Gemstone (Sedimentary classification)
Chert (variously identified as Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Script Jasper
Cryptocrystalline Quartz (SiO2) with fossiliferous inclusions
sedimentary
Amber
Amber (C10H16O)
mineral
Amber
Organic gemstone (Succinite)
mineral
Amber
Succinite (organic mineraloid); Chemical formula: C10H16O
mineral
Baltic Amber (Butterscotch or Egg Yolk Variety)
Succinite (chemical formula: C10H16O)
Organic Gemstone (not a rock or mineral)