Anthracite Coal
Anthracite (high-rank coal / Carbon)
metamorphic
Category
Sedimentary Or Metamorphic (Low Grade)
Browse sedimentary or metamorphic (low grade) specimens identified by the Rock Identifier community.
Emerald (Tumbled Beryl)
Beryllium Aluminum Silicate (Be3Al2Si6O18) with Chromium/Vanadium impurities
mineral
Glauconitic Sandstone (Greensand)
Glauconitic Sandstone ((K, Na)(Fe3+, Al, Mg)2(Si, Al)4O10(OH)2)
sedimentary
Ironstone concretion / Limonitic Sandstone
Goethite/Hematite Cemented Sandstone (Hydrated Iron Oxide)
sedimentary
Ironstone Concretion (Limonite/Goethite)
Ironstone (primarily FeO(OH)·nH2O)
sedimentary
Ferruginous Sandstone (Grit)
Clastic Sedimentary (Ironstone-rich Sandstone)
sedimentary
Ferruginous Sandstone (Ironstone)
Ferruginous Sandstone / Limonite-cemented Quartz Sandstone
sedimentary
Foliated Metamorphic Rock (likely Gneiss or Schist)
Gneissic Metamorphic Rock
metamorphic
Ferruginous Sandstone (with possible Epidote/Chlorite coloring)
Sandstone (SiO2 dominated with Fe2O3 staining)
sedimentary
Anthracite Coal
Anthracite (Carbon Content: 86%–98%)
metamorphic
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Blue Chalcedony
Silicon Dioxide (SiO2)
mineral
Gossan (Iron Hat)
Limonitic Gossan (predominantly FeO(OH)·nH2O)
igneous/metamorphic derivative
Moonstone
Orthoclase Feldspar (KAlSi3O8) or Albite mixtures
mineral
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Moonstone
Orthoclase (Potassium Aluminum Silicate), Formula: (K,Na)AlSi3O8
mineral
Anthracite
Anthracite Coal (C)
sedimentary
Serpentine (Greenstone)
Antigorite, Lizardite, and Chrysolite mixture (Mg3Si2O5(OH)4)
metamorphic
Sandstone with Iron Oxide (Limonite/Hematite)
Ferruginous Sandstone (SiO2 with FeO(OH)·nH2O)
sedimentary
Corundum
Corundum (Al2O3)
Mineral
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
mineral
Ironstone Concretion (Ironstone Gourd)
Limonite/Goethite Concretion (FeOO(H))
sedimentary
Chert (variously identified as Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Bog Iron / Limonite Concretion
Goethite/Limonite mixture (FeO(OH)·nH2O)
sedimentary
Green Aventurine
Silicon dioxide (SiO2) with fuchsite inclusions
mineral
Chalcedony (Pink/Gray variety)
Silicon Dioxide (SiO2)
mineral
Magnetite (Lodestone)
Magnetite (Fe3O4)
mineral
Jasper (Red and Yellow)
Silicon Dioxide (SiO2) with iron oxide impurities
sedimentary
Basalt with Epidote (Porphyry)
Basalt (with inclusions of Epidote/Feldspar)
igneous
Aragonite Star Cluster
Aragonite (Calcium Carbonate, CaCO3)
mineral
Chrome Diopside
Magnesium Calcium Silicate (MgCaSi2O6) containing Chromium impurities
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Aquamarine
Beryl (Be3Al2Si6O18 with iron impurities)
mineral
Biotite Schist
Biotite Schist (K(Mg,Fe)3AlSi3O10(OH,F)2)
metamorphic
Pink Opal (Common Opal)
Amorphous Hydrated Silica (SiO2·nH2O)
mineral
Quartz Vein in Host Rock (Likely Slate or Shale)
Hydrothermal Quartz (SiO2) in Pelitic host rock
metamorphic
Red Jasper
Jasper (Silicon Dioxide, SiO2)
mineral
Siltstone with Quartz Vein
Siltstone (primarily SiO2, Al2O3, Fe2O3)
sedimentary
Botryoidal Pyrite
Iron Sulfide (FeS2)
mineral
Unidentifiable Rock Fragment
Uncertain
Ironstone (likely Limonite or Goethite)
Ferruginous sedimentary rock (FeO(OH)·nH2O)
sedimentary