Iolite-bearing Gneiss (Cordierite)
Cordierite (Mg2Al4Si5O18) in Gneiss matrix
Category
Browse mineral (primary constituent) specimens identified by the Rock Identifier community.
Iolite-bearing Gneiss (Cordierite)
Cordierite (Mg2Al4Si5O18) in Gneiss matrix
Rose Quartz
Rose Quartz (SiO2)
Moss Agate
Moss Agate (a variety of Chalcedony, SiO ₂)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Granite
Granite (felsic intrusive igneous rock)
Talc
Talc (Mg₃Si₄O₁₀(OH)₂)
Granite
Granite (a plutonic igneous rock composed primarily of quartz, feldspar, and mica)
Serpentinite
Serpentinite (composed primarily of Serpentine group minerals usually (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4)
Unknown Organic Object (likely a berry or fruit)
Not applicable; this is not a geological specimen. If it were a cranberry, its scientific name would be Vaccinium macrocarpon; if a cherry, it would be Prunus avium or Prunus cerasus.
Rough Emerald (Beryl)
Emerald (Be3Al2(SiO3)6 with Cr/V impurities)
Acicular Azurite (indicated by deep blue, fibrous/fuzzy appearance)
Azurite (Copper Carbonate Hydroxide) - Cu3(CO3)2(OH)2
Mookaite Jasper
Siliceous (chert) sedimentary rock, a form of Jasper
Chert (often referred to as 'Jasper' when red)
Chert (microcrystalline quartz, SiO₂)
Peridot
Olivine (specific variety: gem-quality forsterite), (Mg,Fe)2SiO4
Sandstone
Quartz Arenite (a type of sandstone composed of more than 90% quartz)
Green Aventurine
Silicon Dioxide (SiO2) with Fuchsite inclusions
Aquamarine
Beryl (Be3Al2Si6O18 with iron impurities)
Blue Quartz
Quartz (SiO2) with inclusions
Rutilated Quartz
Quartz with Rutile inclusions (SiO2 with TiO2 inclusions)
Sandstone (Pebble)
Sandstone (arenite, arkose, wacke depending on composition)
Micaceous Rock (likely Muscovite Schist/Gneiss or a Muscovite-rich Specimen)
Predominantly Muscovite (KAl2(AlSi3O10)(F,OH)2), often found in rocks like Muscovite Schist or Muscovite Gneiss.
Amethyst
Quartz variety; chemical formula: SiO₂ (silicon dioxide) with Fe³⁺ impurities
Citrine Geode (or Druzy Citrine)
Silicon Dioxide (SiO₂) - a variety of Quartz
Epidote
Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
Citrine
Quartz (SiO2) - variety Citrine
Sandstone
Sandstone (lithified sand)
Orange Quartz with Hematite inclusions
Quartz (SiO2) with Hematite (Fe2O3) inclusions
Desert Rose (Baryte/Gypsum Rosette)
Baryte (BaSO4) or Gypsum (CaSO4·2H2O)
Lapis Lazuli
Lapis Lazuli (a rock composed primarily of Lazurite (Na,Ca)₈[(S,Cl,SO₄,OH)₂|(Al₆Si₆O₂₄)], with varying amounts of Calcite, Pyrite, and Sodalite.)
Rutilated Quartz
Quartz (SiO2) with Rutile Inclusions (TiO2)
Rutilated Quartz
Quartz (SiO2) with Rutile (TiO2) inclusions
Blue Tiger's Eye
Crocidolite (fibrous riebeckite) silicified to Quartz (SiO2)
Banded Chert / Banded Jasper (likely a variety of Chert/Chalcedony)
Chert (microcrystalline quartz)
Basalt with Plagioclase Feldspar
Basalt (mafic extrusive igneous rock) with plagioclase feldspar phenocrysts
Prehnite
Prehnite, Ca2Al2Si3O10(OH)2
Emerald
Beryl (variety Emerald), Be3Al2Si6O18 with Cr and/or V
Wood Jasper
Siliceous sedimentary rock (variety of Chert/Chalcedony)
Travertine (used in construction, not a 'specimen' in situ)
Travertine
Sandstone
Arenite (general term for sandstone)
Muscovite Mica
Muscovite (KAl₂(AlSi₃O₁₀)(F,OH)₂))
Peridot and Citrine Gemstones (in a ring setting)
Peridot (Olivine: (Mg,Fe)2SiO4), Citrine (Quartz: SiO2)
Sulfur on Aragonite
Sulfur (S) and Aragonite (CaCO3)