Petrified Wood
Silicified wood, primarily composed of Quartz (SiO2)
Mineral, often found in sedimentary deposits
Category
Organic (Anthropogenic)
Browse organic (anthropogenic) specimens identified by the Rock Identifier community.
Learn about Organic (Anthropogenic) in the encyclopedia
View all →
Chert (varietal known as Jasper or Flint)
Silicon Dioxide (SiO2)
Sedimentary Rock
Pyrite
Pyrite (Iron Disulfide), FeS2
Mineral
Banded Chert / Banded Jasper (likely a variety of Chert/Chalcedony)
Chert (microcrystalline quartz)
Metamorphic Rock
Shale or Argillite
Shale (sedimentary) / Argillite (metamorphic)
Sedimentary or Metamorphic (low-grade)
Amber
Fossilized Tree Resin (Amorphous Hydrocarbon)
Mineral
Amber
Fossilized tree resin (not a true mineral as it is organic and amorphous); Chemical formula is highly variable, but often approximated as C10H16O.
Mineral
Wood Jasper
Siliceous sedimentary rock (variety of Chert/Chalcedony)
Sedimentary
Travertine (used in construction, not a 'specimen' in situ)
Travertine
Sedimentary
Pyrite
Pyrite (Iron sulfide, FeS₂)
mineral
Chalcedony Geode
Chalcedony (SiO2) within a geode structure
Mineral Geode/Sedimentary or Volcanic related
Baroque Pearl (and potentially a small Sapphire/Blue Topaz)
Pearl: Calcium Carbonate (aragonite or calcite) with conchiolin. Sapphire: Aluminum Oxide (Al2O3). Blue Topaz: Al2SiO4(F,OH)2.
Organic Gemstone (for pearl), Mineral (for sapphire/topaz)
Anthracite Coal
Anthracite (Carbon-based organic sedimentary rock exposed to metamorphic heat/pressure; Chemical composition is approximately 86%–98% Carbon)
metamorphic
Shale (possibly)
Shale (fine-grained clastic sedimentary rock)
sedimentary
Ambergris
Physeter macrocephalus excreta (Ambergris)
mineraloid / organic geological find
Ambergris
Ambra grisea
Organic (often found by beachcombers)
Ambergris (Sea Wax)
Physeter macrocephalus fecalith
Organic geological/oceanic specimen
Baltic Amber (Butterscotch or Egg Yolk Variety)
Succinite (C10H16O)
Organic Gemstone (fossilized resin)
Ambergris
Ambrein (C30H52O)
mineraloid / organic geological substance
Fossilized Shark Teeth
Carcharhiniformes or Lamniformes species (common mineral: Fluorapatite/Ca5(PO4)3F)
sedimentary (fossilized organic matter)
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)
Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
Organic Gemstone (Sedimentary classification)
Hand-Drawn Trading Card (Amateur Artwork)
Cellulose-based substrate with wax/graphite/ink deposit (n/a for minerals)
Organic/Synthetic Composite (Paper and Pigment)
Orange Tabby (Felis catus)
Felis silvestris catus (variety: Red Mackerel Tabby)
Organic/Biological specimen (Non-Mineral)
Red Coral
Corallium rubrum (for precious red coral), although other species like Corallium japonicum and Paracorallium are also used.
Organic Gemstone (not a rock or mineral in the traditional sense, but bio-mineralized material)
Red Swirl Beads (Likely Resin or Glass, simulating Red Jasper or Agate)
N/A (for the beads as pictured); Red Jasper: SiO2 (Chert variety); Red Agate: SiO2 (Chalcedony variety)
Organic (if resin) or Synthetic (if glass); simulating Sedimentary or Metamorphic (for natural stones)
Granite
Intrusive Igneous Rock
igneous
Granite
Phaneritic felsic intrusive igneous rock
igneous
Granite
Intrusive igneous rock
igneous
Quartzite
Metamorphic Quartz Rock
metamorphic
Granite
Plutonic Igneous Rock
igneous
Pegmatite (Granitic)
Granitic Pegmatite containing Quartz, Feldspar, and Tourmaline (Schorl)
igneous
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Red Quartzite
Quartzite (SiO2)
metamorphic
Granite
Intrusive igneous rock
igneous
Granite
Intrusive Igneous Rock
igneous
Granite
Intrusive Igneous Rock
igneous
Fossilized Syringopora Coral (Organ Pipe Coral Fossil)
Syringopora sp. (Class Anthozoa, Order Tabulata)
fossil
Greenstone
Metabasalt / Greenstone (low-grade metamorphic rock)
metamorphic
Granite
Intrusive Igneous Rock
igneous
Biotite Schist
Metamorphic Rock (Schist)
metamorphic