Travertine (used in construction, not a 'specimen' in situ)
Travertine
Sedimentary
Category
Organic (Pseudo Geological)
Browse organic (pseudo geological) specimens identified by the Rock Identifier community.
Conglomerate
Conglomerate
Sedimentary Rock
Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
Organic Gemstone (Sedimentary classification)
Shale
Shale
sedimentary
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)
Shale or Argillite
Shale (fine-grained clastic sedimentary rock) or Argillite (low-grade metamorphic rock derived from shale)
Sedimentary or Metamorphic (low grade)
Chalcedony Geode
Chalcedony (SiO2) within a geode structure
Mineral Geode/Sedimentary or Volcanic related
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
Ambergris (Sea Wax)
Physeter macrocephalus fecalith
Organic geological/oceanic specimen
Shale (possibly)
Shale (fine-grained clastic sedimentary rock)
sedimentary
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)
Chert Concretion
Microcrystalline Quartz (SiO2) in Carbonate Matrix
sedimentary
Sandstone Concretion
Limonitic Sandstone Concretion
sedimentary
Druzy Chalcedony/Quartz on Fluorite core
Silicon Dioxide (SiO2) on Calcium Fluoride (CaF2)
mineral
Tumbled Jasper and Tiger's Eye
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Pyrite (Pseudomorph)
Iron Sulfide (FeS2)
mineral
Petrified Wood
Silicified Wood (primarily SiO2)
fossil
Ferruginous Sandstone with Concretion
Sandstone (SiO2 dominated with Fe2O3 cement)
sedimentary
Lepidolite
K(Li,Al)3(Si,Al)4O10(F,OH)2
Mineral
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Dendritic Limestone
Calcite with Manganese Oxide (Manganese Dendrites)
sedimentary
Petrified Wood
Silicified wood (Quartz pseudomorph after wood)
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Chert Concretion
Sedimentary Cryptocrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2 / Quartz pseudomorph after wood)
fossil
Greenish Metamorphic Rock (likely containing epidote or chlorite)
Metamorphic rock, possibly epidosite or greenstone
Metamorphic
Ironstone Concretion
Ironstone (Limonite/Goethite Concretion)
sedimentary
Pink Aragonite
CaCO3
mineral
Quartz Vein in Greenstone
Hydrothermal Quartz (SiO2) with Chlorite/Epidote Schist host rock
metamorphic
Red Tiger's Eye
Silicon Dioxide (SiO2) with iron oxide inclusions
gemstone
Limestone
Sedimentary Rock (Primarily CaCO3)
sedimentary
Limonite (Ironstone Concretion)
Limonite: FeO(OH)·nH2O
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Dendrite (Manganese Oxide Dendrites)
Psilomelane or Pyrolusite on Matrix (typically MnO2)
mineral
Limonite/Hematite Ironstone
Goethite-rich Ironstone (FeO(OH) · nH2O)
sedimentary
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2)
metamorphic
Limonite (often after Pyrite)
Limonite (FeO(OH)·nH2O)
mineral
Dendritic Jasper
Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions
sedimentary
Limonite/Goethite Nodule
Iron Oxyhydroxide (primarily FeO(OH)·nH2O)
mineral
Tumbled copper-bearing rock, likely chrysocolla-bearing basalt or copper ore
Chrysocolla (hydrated copper phyllosilicate, approximately Cu₂H₂Si₂O₅(OH)₄·nH₂O) in a dark volcanic host
mineral
Limonite Geode / Ironstone Concretion
Hydrated iron oxide-hydroxide (FeO(OH)·n H2O)
sedimentary
Limonite
FeO(OH)·nH2O (Hydrated iron oxide)
mineral