Limonite/Hematite Ironstone
Goethite-rich Ironstone (FeO(OH) · nH2O)
Category
Browse igneous and metamorphic derivative (weathered) specimens identified by the Rock Identifier community.
Limonite/Hematite Ironstone
Goethite-rich Ironstone (FeO(OH) · nH2O)
Ironstone Concretion (Moqui Marble type)
Iron oxide concretion (Goethite/Hematite and Sandstone)
Yellow Ochre / Limonite
Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)
Limonite (Hydrated Iron Oxide / Bog Iron)
FeO(OH)·nH2O
Biotite Schist
Biotite Schist (K(Mg,Fe)3AlSi3O10(OH,F)2)
Sunstone and Green Aventurine
Sunstone: (Ca,Na)[(Al,Si)2Si2O8] (Plagioclase Feldspar Group); Green Aventurine: SiO2 (Quartz)
Chert (specifically Gray/Black Chert)
Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)
Gneiss (Metamorphic Rock)
Gneiss
Granite
Granite (a common rock type, not a single mineral species)
Quartz Pebble
Silicon Dioxide (SiO2)
Green Sea Glass
Amorphous Silica (man-made glass), SiO2 + additive metal oxides
Chert (Field Stone/Pebble)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Carnelian Agate
Silicon Dioxide (SiO2) with iron oxide impurities
Fossiliferous Limestone (Crinoidal)
Calcite-bearing bioclastic packstone (CaCO3)
Pyrite with Limonite/Goethite Alteration (Pseudomorph)
Iron Sulfide (FeS2) transitioning to Hydrated Iron Oxides (FeO(OH)·nH2O)
Sea Glass (Cobalt Blue)
Amorphous Silica (Glass with Cobalt additives)
Chert (vuggy variety)
Microcrystalline silica (SiO2)
Fossilized Bone Fragment
Permineralized Skeletal Element (Likely Vertebrate)
Granite Cobble
Felsic Intrusive Igneous Rock (composed of Quartz, Alkali Feldspar, and Plagioclase)
Banded Gneiss
Gneiss (Metamorphic Rock)
Quartz Pebble (Water-Worn)
Silicon Dioxide (SiO2)
Chert (Jasper/Flint variety)
Microcrystalline quartz (SiO2)
Limonite (Iron-rich Siltstone / Sandstone base)
Hydrous ferric oxide mixture (FeO(OH)·nH2O)
Chert (River Pebble)
Microcrystalline Quartz (SiO2)
Red Jasper (Opaque Chalcedony)
Jasper / Silicon Dioxide (SiO2) with Ferric Iron inclusions
Greenschist
Greenschist (Actinolite-Chlorite Schist)
Pyrite
Pyrite (Iron Disulfide), FeS2
Mixed Gemstone Bracelet
Mixed natural minerals and rocks (e.g., Rhodonite, Malachite, Sodalite, Rose Quartz, Black Tourmaline, Quartz/Chalcedony variants)
White Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Quartz (Milky Quartz with Iron Staining)
Silicon Dioxide (SiO2)
Chert (Nodule)
Silicon Dioxide (SiO2)
Chert
Chert (SiO2)
Quartz (River Pebble)
Silicon Dioxide (SiO2)
Chert / Flint
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Orthoclase Feldspar
KAlSi3O8 (Potassium Aluminum Silicate)
Epidote (likely Unakite component or Epidosite)
Epidote (Ca2(Al2Fe)(SiO4)(Si2O7)O(OH))
Muscovite Mica
KAl2(AlSi3O10)(F,OH)2
Epidote
Epidote - {Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Green Moonstone (Garnierite)
Nickel-bearing Magnesium Silicate (often a mix of Serpentine and Talc/Chlorite groups)
Garnet (Almandine variety)
Almandine Garnet (Fe3Al2(SiO4)3)
Banded Agate
Silicon Dioxide (SiO2)