Pyrite
Iron Sulfide (FeS2)
Category
Browse mineral pseudomorph specimens identified by the Rock Identifier community.
Pyrite
Iron Sulfide (FeS2)
Mica Schist or Muscovite
KAl2(AlSi3O10)(OH)2
Limonite with Gossan / Iron Ore
Hydrated iron oxide-hydroxide, approximately FeO(OH)·nH2O
Graphite
Graphite (Carbon, C)
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(F,OH)2)
Sodalite
Na8Al6Si6O24Cl2
Fluorite
Calcium fluoride (CaF2)
Banded Sandstone (Water-worn Pebble)
Arenite with mineral banding
Fossil Shark Tooth
Carcharocles (Otodus) sp. or similar fossilized Chondrichthyes tooth
Gneiss (specifically Banded Gneiss)
Gneiss
Limonite
FeO(OH)•nH2O
Polished copper-bearing mineral specimen, likely malachite-rich copper ore
Malachite, Cu₂CO₃(OH)₂, possibly mixed with chrysocolla or limonite
Bornite
Bornite (Cu5FeS4)
Quartz Crystal
Silicon Dioxide (SiO2)
Quartz Pebble
Quartz (Silicon Dioxide - SiO2)
Limonite Stained Basalt
Hydrated Iron Oxide on Mafic Volcanic Rock (FeO(OH)·nH2O)
Granite
Intrusive Igneous Rock
Quartz-rich pegmatite fragment
Granite-family pegmatite; chiefly quartz (SiO₂), feldspar, and black mica (biotite)
Granite with Mafic Xenolith
Intrusive Igneous Rock (Felsic to Intermediate)
Gneiss
Gneiss (foliated metamorphic rock)
Amygdaloidal Basalt with Quartz Veining
Basalt (Extrusive Igneous Rock) with Quartz (SiO2) veining
Granite
Granite (Phaneritic Quartz-Feldspar Plutonic Rock)
Granite
Granite (Felsic Plutonic Rock)
Granite
Felsic intrusive igneous rock
Banded Sedimentary Rock
Stratified Siliciclastic / Arenite or Siltstone with Mineral Bands
Fossil Sea Urchin (Echinoid)
Echinoidea fossil (often replaced by silica or calcite)
Nephrite Jade
Nephrite
Blue Apatite
Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)
Quartz Vein in Sedimentary Rock
Silicon Dioxide (SiO2) with host Chert or Limestone
Olivine (Peridot)
Magnesium Iron Silicate (Mg,Fe)2SiO4
Pyrite with Quartz
Iron Sulfide (FeS2) with Silicon Dioxide (SiO2)
Mica Schist / Granite
Mica Schist (Silicate metamorphic rock)
Gravel and Pebbles
Unconsolidated rock fragments / detrital sediment
Fossilized Shark Tooth
Chondrichthyes (Class)
Fossil Shark Tooth
Carcharodon or Carcharias fossil (Vertebrate Fossil)
Kidney Stone (Urolith / Calcium Oxalate Stone)
Calcium Oxalate Monohydrate (Whewellite) / Calcium Oxalate Dihydrate (Weddellite)
Quartz Mineral
Silicon Dioxide (SiO2)
Quartz Mineral
Silicon Dioxide (SiO2)
Sandstone (with Limonite staining)
Arenite (primarily SiO2 with FeO(OH)·nH2O)
Pyrite in Quartz
Iron Sulfide (FeS2) in Silicon Dioxide (SiO2)
Quartz on Schist
Silicon Dioxide (SiO2) on Foliated Metamorphic Rock
Mixed Mineral Assortment (Pyrite, Kyanite, Agate, Jasper)
FeS2 (Pyrite), Al2SiO5 (Kyanite), SiO2 (Agate/Jasper)