Howardites
Topic

#Carbonaceous chondrites

Dark, carbon-rich meteorites that carry water-bearing minerals and organic molecules.

Lessons (4)

Courses (5)

Famous meteorites (7)

  • AllendeThe meteorite that fell on a Mexican village months before Apollo 11 – and turned out to hold the oldest solids in the Solar System.
  • KaidunA small stone that fell on a military base in Yemen in 1980 and turned out to be a jigsaw of many different worlds.
  • MurchisonA stone that fell on an Australian town in 1969, packed with the chemical building blocks of life.
  • OrgueilA crumbly black meteorite from 1864 whose chemistry is the closest match on Earth to the Sun itself.
  • Sutter's MillIn 2012 a rare carbon-rich meteorite fell on the very spot where the California Gold Rush began – and weather radar helped find it.
  • Tagish LakeA fragile carbon-rich meteorite that fell onto a frozen Canadian lake in 2000 and was collected without being touched by bare hands.
  • WinchcombeThe 2021 fireball filmed across Britain that delivered the UK's first carbonaceous chondrite – onto a family's driveway.

Meteorite types (16)

  • Carbonaceous chondritesRare, often dark chondrites rich in carbon, water-bearing minerals and organic compounds, including the building blocks of life.
  • CB chondrites (bencubbinites)More than half metal, with chondrules made in a planet-sized collision. CB chondrites, named after Bencubbin in Australia, are more than 50%
  • CH chondrites'High metal' carbonaceous chondrites with tiny chondrules. CH chondrites are rich in iron-nickel metal, about 20% of the rock by vol
  • ChondritesPrimitive stones that never melted, made of the first solids of the Solar System. The most common meteorites of all.
  • CI chondritesThe chemically most primitive rocks known: their make-up matches the Sun's. CI chondrites, named after Ivuna in Tanzania, match the comp
  • CK chondritesHeated, highly oxidised carbonaceous chondrites, cousins of the CVs. CK chondrites, named after Karoonda in Australia, are unusual among car
  • CM chondritesWater-rich carbonaceous chondrites full of organic molecules, Murchison and Winchcombe among them.
  • CO chondritesSmall-chondrule carbonaceous chondrites, close relatives of the CMs. CO chondrites, named after Ornans in France, have very small chondrules
  • CR chondritesMetal-bearing carbonaceous chondrites with some of the most pristine organic matter known.
  • CV chondritesLarge chondrules and big white inclusions, the oldest solids in the Solar System. Allende is the classic.
  • Eagle Station pallasitesA tiny grouplet of pallasites with iron-rich olivine and nickel-rich metal, from a separate parent body.
  • HowarditesBroken rubble from the surface of asteroid Vesta, mixing crust and mantle rocks. Howardites are regolith breccias: rocks made from the broke
  • IIC ironsA rare group of plessitic octahedrites. IIC irons are plessitic octahedrites with about 9–11.5% nickel. Only a few are known.
  • IIF ironsA small group of magmatic irons. IIF is a small magmatic group of irons with distinctive trace-element patterns. Only a handful are known.
  • IIIF ironsA small group with very low gallium and germanium. IIIF irons are medium to coarse octahedrites with about 7–8% nickel and very low gallium
  • K chondrites (Kakangari grouplet)A tiny grouplet with a mix of features found in no other chondrite group. K chondrites are named after Kakangari in India, which fell in 189

Space missions (2)

  • MBR ExplorerThe United Arab Emirates' planned tour of the asteroid belt, ending with a landing.
  • MMX (Martian Moons eXploration)Japan's mission to bring back the first sample from a moon of Mars. Mars has two small, dark moons, Phobos, about 22 kilometres across,

Meteorite minerals (19)

  • AllendeiteA scandium zirconium oxide named after the Allende meteorite. Allendeite is an oxide of scandium and zirconium, two of the most refractory e
  • AndraditeA calcium–iron garnet that grew during alteration in CV chondrites such as Allende.
  • AwaruiteA nickel-rich iron alloy found in some oxidised carbonaceous chondrites. Awaruite is an alloy with about three nickel atoms for each iron at
  • CalciteCalcium carbonate that grew from water inside carbonaceous asteroids, and also forms as meteorites weather on Earth.
  • DavisiteA scandium-rich pyroxene from an ultra-refractory inclusion in Allende. Davisite is a pyroxene related to diopside in which scandium and alu
  • DiopsideA calcium–magnesium pyroxene found in the oldest solids of the Solar System and in many chondrules.
  • FerrihydriteA poorly crystalline iron oxyhydroxide found in the matrix of CI chondrites. Ferrihydrite is a hydrous iron oxide with very small, poorly or
  • GrossmaniteA pyroxene containing titanium in an unusual state, found in the oldest inclusions in Allende.
  • HedenbergiteThe iron-rich calcium pyroxene, which grew in carbonaceous chondrites as fluids altered the rock.
  • HexamolybdenumA tiny alloy of molybdenum and platinum-group metals from the oldest inclusions in Allende.
  • Hibonite-(Fe)An iron-rich hibonite that formed when an ancient inclusion in Allende was altered.
  • HiboniteA calcium aluminium oxide, among the very first minerals to condense in the Solar System.
  • HutcheoniteA titanium-bearing garnet that grew when a CAI in Allende was altered on its parent asteroid.
  • KangiteA scandium-rich oxide from the ultra-refractory inclusions of Allende. Kangite is an oxide dominated by scandium with titanium and other ref
  • MajindeiteA magnesium molybdenum oxide formed when tiny metal nuggets in Allende were oxidised.
  • MeliliteA calcium aluminium silicate series, gehlenite to åkermanite, that makes up much of the white inclusions in Allende.
  • NephelineA sodium aluminium silicate that replaces melilite and anorthite in CAIs that were later altered.
  • PanguiteA titanium oxide rich in scandium and zirconium, from one of the oldest grains in the Solar System.
  • TistariteA titanium oxide with titanium in its rare three-charge state, from the earliest solids in Allende.

Glossary (17)

Questions and answers (24)

Impact events (1)

  • Tagish Lake, 2000A fireball seen by satellites that dropped some of the most fragile meteorites known.

Micrometeorites (3)

History (1)

People (4)

  • Edward AndersThe Chicago cosmochemist whose table of Solar System element abundances became a standard, and whose team first found stardust older than th
  • Gerald WasserburgThe Caltech geochemist whose super-clean laboratory dated Moon rocks and found the traces of aluminium-26 in the Allende meteorite.
  • Roy ClarkeThe Smithsonian curator who helped collect and describe the Allende meteorite in 1969 and co-discovered the mineral tetrataenite. Roy S. Cla
  • The Wilcock familyThe Gloucestershire family who found black fragments of the Winchcombe meteorite on their driveway the morning after it fell in 2021.

Museums and collections (6)

Strewn fields (2)

  • The Allende strewn fieldThe largest carbonaceous chondrite ever found, spread along a 50-kilometre field in the Chihuahua desert.
  • The Murchison strewn fieldA Sunday-morning shower of carbon-rich stones over a country town in Victoria, which became one of the most studied rocks in the world.

Meteorite law (1)

  • Meteorite law in MexicoNo meteorite-specific rule that we can confirm. Allende stones have been collected and traded since 1969; ask before exporting important spe

Meteorites (the 60 largest of 1,616)