Quartz (milky variety)
SiO2 (Silicon Dioxide)
Mineral
Category
Organic (Geological Relative)
Browse organic (geological relative) specimens identified by the Rock Identifier community.
Amethyst Quartz
SiO2 (Silicon Dioxide)
Mineral
Sunstone
Plagioclase Feldspar (specifically Oligoclase variety containing hematite or goethite inclusions)", composition: (Ca,Na)(Al,Si)2Si2O8
Mineral
Fluorite
Fluorite (Calcium Fluoride, CaF2)
mineral
Sodalite
Sodalite (Na4Al3Si3O12Cl)
Mineral
Gneiss (Metamorphic Rock)
Gneiss
metamorphic
Jade (likely Nephrite or Jadeite)
Nephrite (a variety of actinolite, Ca2(Mg,Fe)5Si8O22(OH)2) or Jadeite (NaAlSi2O6)
Metamorphic rock (for Nephrite and some Jadeite); Mineral (for Jadeite)
Amazonite
Amazonite (KAlSi3O8, a variety of Microcline)
Mineral
Citrine
Quartz (SiO2) - specifically, a variety of macrocrystalline quartz
mineral
Black Obsidian
Obsidian, volcanic glass (Amorphous SiO₂)
Igneous Rock
Jade (likely Nephrite Jade based on appearance)
Nephrite (a variety of actinolite, Ca2(Mg,Fe)5Si8O22(OH)2)
Mineral
Peridot
Olivine ((Mg,Fe)2SiO4)
Mineral
Serpentinite
Serpentinite (Mg, Fe, Ni, Al, Zn)2-3(Si, Al, Fe)2O5(OH)4
metamorphic
Granite
Granite (a felsic intrusive igneous rock composed primarily of quartz, feldspar, and mica)
igneous
Red Jasper
Jasper (a variety of Chalcedony, SiO₂ with impurities)
Mineral
Tektite (likely Australite)
Tektite (no specific chemical formula as it's a natural glass of variable composition, mostly SiO2, Al2O3, FeO, MgO, CaO, K2O, Na2O, TiO2)
Mineral (specifically a mineraloid)
Larimar
Pectolite (a variety of pectolite, NaCa2Si3O8(OH))
Mineral
Quartzite
Quartzite (primarily SiO2)
Metamorphic
Sandstone (likely a river or beach pebble)
Sandstone (a clastic sedimentary rock)
Sedimentary Rock
Chalcedony (or a variety of Chalcedony, likely Agate or Jasper)
Chalcedony (SiO₂)
Mineral (or mineraloid if microcrystalline)
Red Jasper
Silicon Dioxide (SiO₂)
Sedimentary Rock (Cryptocrystalline Quartz)
Granite (tumbled pebble)
Granite (Plutonic Igneous Rock)
Igneous Rock
Rough Green Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Malachite
Malachite (Cu2CO3(OH)2)
mineral
River Stone / Pebble
Clastic Sediment (composed largely of Quartz, Feldspar, and various rock fragments)
Mineral, Sediment
Garnet (likely Almandine or a blend)
Garnet group: X3Y2(SiO4)3, where X can be Ca, Mg, Fe2+, Mn2+ and Y can be Al, Fe3+, Cr3+. Given the dark, somewhat reddish-brown appearance in the image, it's likely Almandine (Fe3Al2(SiO4)3) or a mix with other iron-rich garnets.
Mineral
Garnet (likely Almandine, Pyrope, or a blend)
Garnet group minerals: X3Y2(SiO4)3, where X and Y represent various metal ions (e.g., Almandine: Fe3Al2(SiO4)3, Pyrope: Mg3Al2(SiO4)3)
Mineral
Cinnabar
Cinnabar (HgS)
mineral
Epidote in Quartz
Quartz with Epidote inclusions (SiO2 with Ca2(Al,Fe)3(SiO4)3(OH) inclusions)
Mineral
Pink Aragonite
CaCO3
mineral
Veined Quartz
SiO2 (Silicon Dioxide)
Mineral
Clear Quartz (or Rock Crystal)
Quartz (SiO₂)
Mineral
Carnelian
Carnelian (a variety of Chalcedony, SiO2)
Mineral
Jade
Jadeite or Nephrite
Mineral/Mineraloid
Quartzite
Quartzite (primarily SiO2)
Metamorphic
Amethyst
Amethyst (SiO₂)
Mineral
Diamond
Diamond (C)
Mineral
Banded Calcite (often sold as 'Mexican Onyx' or 'Green Onyx')
Calcite (CaCO3)
sedimentary
Granite
Granite (a plutonic igneous rock composed primarily of quartz, feldspar, and mica)
igneous
Larimar
Pectolite (a variety of pectolite, NaCa2Si3O8(OH))
Mineral
Citrine
Quartz (SiO₂)
Mineral
Demantoid Garnet on Matrix
Demantoid (variety of Andradite Garnet) - Ca3(Fe3+)2(SiO4)3
mineral