Anthracite Coal
Anthracite (Carbon-based organic sedimentary/metamorphic rock)
metamorphic
Category
Organic (Biological Specimen)
Browse organic (biological specimen) specimens identified by the Rock Identifier community.
Quartz Geode
Silicon Dioxide (SiO2)
sedimentary
Petrified Wood
Silicified wood (SiO2)
sedimentary
Fossilized Gastropod (Snail)
Class Gastropoda (internal mold or 'steinkern')
sedimentary
Chert Pebble with Quartz Veins
Microcrystalline Quartz (SiO2)
sedimentary
Shale
Shale (fine-grained clastic sedimentary rock)
Sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified wood (primarily quartz replacing organic cellulose)
fossil
Anthracite Coal
Anthracite (Metamorphic/High-grade Sedimentary Coal)
sedimentary
Ambergris (Marine Coprolite/Subfossil)
Marine organic coprolite / Ambergris (Physeter macrocephalus metabolite)
fossil
Bituminous Coal
Organic Sedimentary Rock (composed mostly of carbon with sulfur and hydrogen)
sedimentary
Travertine (Tufa)
Calcium Carbonate (CaCO3)
sedimentary
Petrified Wood
Silicified wood (Quartz / Chalcedonized wood, SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Pink Opal
Hydrated Silica (SiO2·nH2O) with Palygorskite inclusions
Mineraloid
Petrified Wood
Silicified Wood (SiO2)
fossil
Petoskey Stone
Hexagonaria percarinata (Fossilized Coral)
sedimentary
Anthracite Coal
Anthracite (Carbon-rich metamorphic coal)
metamorphic
Red Jasper (Plum or Brick variety)
Silicon Dioxide (SiO2) with iron oxide inclusions (Hematite)
sedimentary (chemical/biological origin)
Petrified Wood
Silicified wood (primarily SiO2)
sedimentary
Petrified Wood
Silicified Wood / Xylopal
fossil
Petrified Wood
Silicified wood (primarily quartz, SiO2)
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily quartz/chalcedony replacing organic wood structures, SiO2)
fossil
Pearl (Cultured or Natural)
Aragonite (CaCO3) with Conchiolin
Organic Mineraloid
Amber
Succinite (a specific high-quality amber from the Baltic)
Organic Mineraloid
Petrified Wood
Silicified Wood (primarily quartz/chalcedony replacing organic wood structure, SiO2)
sedimentary
Amber (Cherry Amber)
Succinite (C10H16O)
Organic Gemstone
Popcorn
Zea mays everta (P. Wilson) (Botanical name for the corn variety)
Organic/Biogenic
Pink Opal / Peruvian Opal
Hydrated amorphous silicon dioxide (SiO2·nH2O)
Mineral
Amber
Succinite (fossilized resin)
Organic Mineraloid
Amber (Burmite)
Fossilized tree resin (Succinite variant)
Organic mineraloid
Amber
Succinite (Fossilized Resin C10H16O)
Organic Mineraloid
Polished petrified wood
Silicified wood, primarily microcrystalline quartz (SiO₂) replacing organic tissue
fossil
Petrified Wood
Silicified Wood / Fossilized Wood (SiO2)
sedimentary
Petrified Wood
Silicified wood (Quartz / Chalcedony replacement)
fossil
Amber (Butterscotch/Egg Yolk Variety)
Succinite (Approx. C10H16O)
Organic Gemstone
Ambergris
Ambrein (C30H52O Derivative)
Organic (Zoogenic)
Amber
Succinite (Formula: C10H16O)
Organic Mineraloid
Baroque Pearl
Calcium Carbonate (Aragonite or Calcite) and Conchiolin
Organic Gemstone