Ureilite
Ureilites are a rare type of stone meteorite , a subgroup of achondrites that have a unique mineralogical composition.
composition
A technical name for the ureilite would be olivine - pigeonite - achondrite. Compared to most other meteorites, ureilites tend to have a high proportion of carbon (on average 3% by weight) in the form of graphite and nano- diamonds . The diamonds (rarely more than a few micrometers in diameter) were probably created due to the high pressure shock waves caused by collisions of the urilite base with other asteroids. A distinction is made between monomictic (unrecognized) and polymictic Ureilites. Monomictic ureilites are igneous rocks consisting of coarse-grained olivine ( forsterite ) and clinopyroxene (pigeonite) as well as accessories such as graphite, diamond, lonsdaleite , nickel-iron or troilite . Polymictic ureilites have various clasts of monomictic ureilite, chondrites, and others. The origin of the Ureilite is not yet exactly known. According to one theory, ureilites were formed inside a base with accumulated crystals.
Well-known Ureilite
One of these Ureilites is the 2008 TC3 ( identified as an F-type asteroid )
literature
- Martin Okrusch, Siegfried Matthes: Mineralogie, 8th edition, Springer 2010, p. 514, Google Books