Limonite Concretion
Limonite (FeO(OH)·nH2O) Pseudomorph
Category
Browse sedimentary or metamorphic (low grade) specimens identified by the Rock Identifier community.
Limonite Concretion
Limonite (FeO(OH)·nH2O) Pseudomorph
Marble
Metamorphosed Limestone (main mineral: Calcite, CaCO3)
Quartz on Greenstone
Silicon Dioxide (SiO2) on Altered Igneous Geologic Unit
Weathered iron-rich sandstone or lateritic rock
Ferruginous sandstone/laterite; chiefly quartz (SiO₂) with iron oxides such as hematite and goethite
Ironstone Concretion (Boxwork)
Siderite-Limonite Concretion (FeO(OH)·nH2O)
Siltstone
Siltstone (fine-grained clastic sedimentary rock)
Limonite Concretion
Goethite-rich Concretion (FeO(OH))
Ironstone Concretion / Chert Nodules
Iron-rich Sedimentary Concretion (Fe2O3 / SiO2 mix)
Green Quartzite (Aventurine type)
Quartzite (principally Quartz, SiO2) with inclusions of Fuchsite
Epidosite (Epidote-rich rock)
Epidotalite (primarily Ca2(Al2Fe3+)(SiO4)(Si2O7)O(OH))
Jasper with Epidote
Silicon Dioxide (SiO2) with Calcium Aluminum Iron Silicate Hydrate
Black Beach Pebble (Basalt / Slate)
Basalt / Metamorphic Slate pebble
Emerald
Beryl (Be3Al2(SiO3)6)
Ferruginous Sandstone
Ferruginous Sandstone (Quartz Arenite with Iron Oxide cement)
Epidote and Quartz in Basalt
Epidote [Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)] in Metabasalt
Graphite-rich schist (likely graphite ore)
Graphite-bearing schist; predominantly graphitic carbon (C) with mica, quartz, and possible feldspar
Greenstone
Metabasalt / Greenschist
Onyx (Calcite Onyx / Mexican Onyx)
Calcium Carbonate (CaCO3)
Slate / Greenschist
Foliated Metamorphic Rock (Greenschist/Slate)
Banded Chert or Unakite-like Rock
Epidotized Granulite or Jasperoid Chert
Greenstone
Metabasalt (often contains Chlorite, Actinolite, and Epidote)
Anthracite Coal
Anthracite
Burmese Jadeite
Jadeite (NaAlSi2O6)
Jade (Jadeite or Nephrite)
Jadeite (NaAlSi2O6) or Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2)
Limonite Sandstone
Ferruginous Sandstone (Hydrated Iron Oxide)
Tumbled black-and-gold tiger’s-eye
Quartz pseudomorph after crocidolite; SiO₂ with iron oxides
Anthracite Coal
Anthracite (Hard Coal)
Greenstone or Chlorite Schist
Greenschist / Chlorite schist
Jadeite Jade
Jadeite (NaAlSi2O6)
Jadeite
NaAl(Si2O6)
Serpentine
Antigorite-Lizardite-Chrysotile (Mg3Si2O5(OH)4)
Greenstone / Diabase Porphyry
Porphyritic Diabase (Micro-gabbro)
Quartz with Epidote
Silicon Dioxide (SiO2) with Calcium Aluminum Iron Silicate [Ca2(Al,Fe)3(SiO4)3(OH)]
Rough Garnet (Almandine)
Almandine Garnet (Fe3Al2(SiO4)3)
Jade (likely Nephrite Jade based on appearance)
Nephrite (a variety of actinolite, Ca2(Mg,Fe)5Si8O22(OH)2)
Jadeite Jade
NaAlSi2O6 (Sodium Aluminum Silicate)
Greenstone (Epidote/Chlorite-rich Metabasalt)
Greenschist / Epidosite (Ca2(Al,Fe)3(SiO4)3(OH))
Siderite Concretion in Shale
Iron carbonate (FeCO3) in Mudstone/Shale matrix
Slate with Red Sandstone Landscaping Rock
Foliated Pelitic Metamorphic Rock (Slate) and Ferruginous Sandstone
Rough Emerald (Beryl)
Emerald (Be3Al2(SiO3)6 with Cr/V impurities)
Red Jasper with Quartz Veining
Microcrystalline Quartz (SiO2)
Greenstone
Metamorphic mafic rock (greenschist facies)