869 (Northwest Africa 869)
NWA 869 is one of the most interesting Ordinary Chondrites
found in Northwest Africa. The meteorite was discovered in 2000
near Tindouf in Algeria and some estimates indicate that up to
3000kg in the form of thousands of stones have been found, making it one of the largest
Total Known Weight meteorites to come out of Northwest Africa.
This meteorite has also been given other names including NWA 787, NWA 900
and likely many, many more.
It is a very attractive looking meteorite and has a number of
distinguishing features. When cut and polished, the matrix is
full of colour and chondrules as you can see in the photos
below. Some pieces also display what look like carbonaceous
inclusions and some also show clear brecciation. The stones of
this meteorite vary quite widely which makes classification
difficult. As mentioned, some individuals will show the dark
inclusions and brecciation, while others will not even hint at
it. This meteorite has been classified a number of times by
different institutions around the world and they have all come
up with a different classification. One thing they all agree on
however, is that it's an L-Chondrite!
UCLA originally classified NWA 869 as L4, but later reclassified
it to L5. It has also been classified as L3.9-6 and L6. A couple of these
classifications have also stated that it is brecciated. NWA 869
has now been officially published in Meteoritical Bulletin #90
as an L4-6 fragmental breccia with a Shock Rating of S3 and a
Weathering Level of W1.
NWA 869 (L4-6) -
1000 x 701 (205KB)
NWA 869 - 50g
Endcut showing matrix.
NWA 869 - 47g
Individual with some crust and interior chondrules showing
NWA 869 - Slice
showing the many different characters that make up this
interesting meteorite. Note the dark (Carbonaceous?) inclusions
along with the different coloured zones in the matrix.