Rough Diamond (Bort)
Diamond (C)
Category
Browse mineral (biogenic) specimens identified by the Rock Identifier community.
Rough Diamond (Bort)
Diamond (C)
Limonite/Goethite (Iron Ore)
Hydrous ferric oxides (FeO(OH)·nH2O)
Limonite (Iron Ore)
FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide mixture)
Iron Ore (Limonite and Hematite)
Goethite/Limonite (FeO(OH)·nH2O) and Hematite (Fe2O3)
Pegmatitic granite specimen
Granitic pegmatite, chiefly quartz (SiO₂), feldspar, and mica
Hag Stone
Perforated sedimentary rock (typically sandstone or limestone)
Granite
Intrusive igneous rock
Fossil / Permineralized Bone
Tyrannosaurus rex fossil (Hydroxylapatite replaced by various minerals)
Granite
Phaneritic Felsic Igneous Rock
Granitic Pegmatite with Schorl Tourmaline
Granitic Pegmatite (Schorl: NaFe3Al6(BO3)3Si6O18(OH)4)
Silver Nuggets (Natural or Cast)
Native Silver (Ag)
Quartz Geode
Silicon Dioxide (SiO2) in Geodic Cavity
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Cobaltian Calcite
Cobalt-bearing Calcite (Ca,Co)CO3
Black Spinel
Magnesium Aluminum Oxide (MgAl2O4)
Polished serpentine pebble
Serpentinite, chiefly serpentine-group minerals (chrysotile, lizardite, antigorite)
Serpentinite
Serpentinite, composed mainly of serpentine-group minerals (approximately Mg₃Si₂O₅(OH)₄)
Turquoise and Hematite
Turquoise (CuAl6(PO4)4(OH)8·4H2O) and Hematite (Fe2O3)
Gneiss (likely biotite–quartz–feldspar gneiss)
Foliated gneiss; primarily quartz (SiO₂), feldspar, and biotite mica
Botryoidal Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
Epidote
Epidote (Ca2(Al2,Fe3+)AlSi3O12(OH))
Granite
Phaneritic intrusive igneous rock (Quartz, Feldspar, Mica)
Pink Granite (Unakite-bearing or Epidote-bearing Granite)
Plutonic Igneous Rock (Granite)
Gneiss
Gneiss (High-grade metamorphic rock)
Gneiss
Gneiss
Banded sandstone pebble
Quartz-rich lithic sandstone; exact provenance and composition require testing
Gneiss
Gneiss
Diorite (Salt and Pepper Rock)
Diorite
Gneiss
Gneiss
Concrete with Aggregate
Artificial Conglomerate (Cement and Aggregate)
Gneiss (Banded Gneiss)
Gneiss
Sandstone (likely Arkosic or Lithic)
Clastic Sedimentary Rock (SiO2 with accessory minerals)
Limonite Ironstone
Goethite-Limonite concretion / Iron oxide
Small pale mineral fragment
Unidentified; possibly quartz, calcite, or feldspar
Serpentinite
Serpentine-group minerals, chiefly antigorite, lizardite, and chrysotile; approximate formula Mg3Si2O5(OH)4
Pebble with vesicles, likely basalt
Vesicular basalt; chiefly plagioclase, pyroxene, and iron-magnesium minerals
K-Feldspar (Potassium Feldspar)
Potassium Feldspar (KAlSi3O8)
Mica / Muscovite or Biotite
Phyllosilicate mineral group (e.g., KAl2(AlSi3O10)(OH)2)
Chalcopyrite (Peacock Ore)
Chalcopyrite (CuFeS2)
Botryoidal Chalcedony / Quartz
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Mica (Muscovite or Biotite)
Sheet silicate mineral group (e.g., KAl2(AlSi3O10)(F,OH)2)