Anthracite Coal
Anthracite (high-rank coal)
Category
Browse sedimentary or metamorphic (low grade) specimens identified by the Rock Identifier community.
Anthracite Coal
Anthracite (high-rank coal)
Blue Chalcedony
Silicon Dioxide (SiO2)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Carnelian (Red Chalcedony)
SiO2 (Silicon Dioxide with Iron Oxide inclusions)
Yellow Chalcedony (Agate)
Silicon Dioxide (SiO2)
Iron-rich laterite or weathered ironstone
Ferricrete/limonite-rich ironstone; primarily goethite (FeO(OH)) and hematite (Fe₂O₃), with clay minerals
Ferruginous Sandstone
Ferruginous Sandstone (Quartz grains with Iron Oxide cement)
Gossan
Iron-rich regolith (mainly Limonite and Goethite, FeO(OH)·nH2O)
Ironstone Concretion (Limonite/Goethite)
Ferruginous Sandstone / Ironstone (FeO(OH)·nH2O)
Ironstone Concretion
Siderite or Limonite Concretion
Ferruginous Sandstone (Gozzan)
Iron-rich clastic sedimentary rock with Limonite/Goethite
Bauxite
Bauxite (Al2O3·nH2O)
Limonite/Goethite Concretion
Hydrated Iron(III) Oxide-hydroxide (FeO(OH)·nH2O)
Limonite Concretion
Goethite-Limonite (FeO(OH)·nH2O)
Limonite (Ironstone Concretion)
Limonite (Hydrous ferric oxide mixture, FeO(OH)·nH2O)
Ferruginous Sandstone (Ironstone)
Arenite with Iron-Oxide Cement (FeO(OH)·nH2O / Fe2O3)
Ferruginous Sandstone (with Laterite)
Ferruginous Arenite (FeO(OH)·nH2O)
Ironstone (possibly Bog Iron or Limonite)
Goethite-rich Ironstone (FeO(OH))
Milky Quartz
Quartz (Silicon Dioxide - SiO2)
Pyrite
Iron Sulfide (FeS2)
Yellow Jadeite
NaAlSi2O6 (Sodium Aluminum Silicate)
Epidote
Epidote (Ca2(Al,Fe)3(SiO4)3(OH))
Anthracite Coal
Anthracite
Rounded gray stone, likely slate or fine-grained sandstone
Probable slate (low-grade metamorphosed shale) or lithic sandstone; exact identification requires testing
Turquoise
Hydrated phosphate of copper and aluminum - CuAl6(PO4)4(OH)8·4H2O
Veined Grey Metamorphic Pebble
Quartzo-feldspathic vein in Metabasalt / Serpentinite / Slate
Anthracite Coal
Anthracite
Anthracite Coal
Anthracite (Carbon ≥ 86%)
Garnet in Matrix
Almandine or Spessartine Garnet in Quartz/Schist Matrix (X3Al2(SiO4)3)
Aquamarine
Beryl (Be3Al2Si6O18 with iron impurities)
Kyanite
Kyanite (Al2SiO5)
White Jade
Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2) or Jadeite (NaAlSi2O6)
Serpentinite
Serpentinite (composed primarily of mineral group (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4)
Green Fluorite
Calcium Fluoride (CaF2)
Gneiss
Metamorphic Gneiss
Emerald in Matrix
Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities
Fossiliferous Limestone / Fossil Fragment
Calcium Carbonate (CaCO3) with indeterminate biogenic remains
Anthracite Coal
Anthracite (Metamorphosed Coal)
Beryl (Emerald Variety)
Beryllium Aluminum Silicate (Be3Al2(SiO3)6)
Mixed river gravel (alluvial conglomeratic sediment)
Polymictic alluvium; composition includes quartz, feldspar, chert, granite, basalt, and metamorphic rock fragments
Mossy Rock
Mixed lithology rock with Bryophyta (moss)
Likely tumbled jasper or iron-stained quartzite
Microcrystalline quartz (SiO₂), possibly quartzite with iron-oxide inclusions