Coal
Anthracite / Bituminous Coal
sedimentary
Category
Synthetic Polymer (Synthetic Material)
Browse synthetic polymer (synthetic material) specimens identified by the Rock Identifier community.
Learn about Synthetic Polymer (Synthetic Material) in the encyclopedia
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Iron-rich meteorite candidate
Undetermined Fe–Ni meteorite, possibly an ordinary chondrite or iron meteorite
meteorite
Greenish translucent mineral fragment
Indeterminate; possibly serpentine, epidote, or green glassy feldspar
mineral
Iron-stained quartz-rich rock, likely quartzite or silicified breccia
Quartz (SiO₂), possibly quartzite with limonite/goethite iron oxides
metamorphic
Likely polished bronzite or serpentine-rich rock
Probable bronzite, an iron-bearing orthopyroxene (Mg,Fe)SiO₃; exact identification requires testing
mineral
Jasper
Microcrystalline Quartz (Chalcedony), SiO2
sedimentary
Fulgurite
Fulgurite (Lechatelierite or fused sand/quartz)
mineral
Dinosaur Fossil Tooth
Vertebrate Fossilized Tooth
fossil
Fossil Shark Tooth
Chondrichthyes (class)
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Fossil Shark Tooth
Selachii (fossilized dentition)
fossil
Bivalve Fossil (Fossilized Shell)
Class Bivalvia (fossilized in Calcium Carbonate/Aragonite)
fossil
Fossil Coral
Scleractinia or Anthozoa (Fossilized)
fossil
Ironstone Concretion
Ironstone (primarily Siderite or Limonite)
sedimentary
Bivalve Fossil (Internal Mold)
Bivalvia (Phalladomya or similar genus)
fossil
Petrified Wood
Silicified Wood (primarily SiO2)
fossil
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert Nodule (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Limonite
Limonite (Hydrated iron(III) oxide-hydroxide) FeO(OH)·nH2O
mineral
Slag (Industrial Glassy Byproduct)
Anthropogenic silicate byproduct (Slag)
Mineral-like byproduct (often mistaken for igneous rock or meteorite)
Limonite (vibrant yellowish-brown iron oxide)
Limonite (FeO(OH)·nH2O)
mineral
Yellow Chert (Chalcedony)
Microcrystalline Quartz (SiO2)
sedimentary
Anthracite Coal
Anthracite
sedimentary
Limonite (Iron Ore)
Limonite (Hydrated Iron Oxide, FeO(OH)·nH2O)
Mineral
Jasper
Silicon dioxide (SiO2)
sedimentary
Pink Banded Onyx (Mexican Onyx / Calcite)
Calcite (CaCO3) - microcrystalline calcium carbonate
sedimentary
Fluorite (Green Fluorite)
Calcium Fluoride (CaF2)
mineral
Tumbled prehnite (probable)
Prehnite, Ca₂Al₂Si₃O₁₀(OH)₂; possibly epidote- or chlorite-bearing
mineral
Diamond (Cut Specimen)
Diamond (pure carbon, C)
mineral
Diamond
Natural Diamond (Carbon, C)
mineral
Diamond
Carbon (C)
gemstone
Sandstone
Arenite (SiO2 based)
sedimentary
Red Sandstone
Arenite (primarily Quartz with Hematite cement)
sedimentary
Rhodonite
Rhodonite, manganese inosilicate — MnSiO₃; the specimen may include quartz, feldspar, and black manganese-oxide minerals in the matrix
mineral
River-worn Chert
Microcrystalline Quartz (SiO2)
sedimentary
Weathered, porous limestone (probable fossiliferous limestone)
Calcite-rich limestone; predominantly CaCO₃
sedimentary
Crushed Limestone
Calcium Carbonate (CaCO3)
sedimentary
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral