571.5 grams. LL6
TKW 714 grams. Fall not observed. Purchased 2000, Rissani, Morocco.
  
jnmczurich writes:
NWA 757 (S4, partly S6, W2) is one of 2954 different LL6 chondrites according Met Bulletin (Sep 13, 2024). But this one is a bit special because of its very first discovery of shock-induced purple-blue high pressure mineral ringwoodite in a LL chondrite, sitting in olivine fragments inside of the wide shock veins of NWA 757.
NWA 757 was heavy shocked in space twice. In the first event, were the first melt assemblage happend, majoritic garnet, ringwoodite plus magnetite-magnesiowüstite, crystallized at pressures of 20-25 GPa. At that time the shock veins were build. A second shock event in space at pressure of about 15 GPa, was creating also a melt assemblage, consisting clinopyroxene and wadsleyite, suggesting a second veining event under lower pressure conditions.
There are two interesting publications available:
1.) A.Bischoff, LPSC, 2002, 33, abs. #1264
2.) J.Hu, T.G.Sharp, MAPS 51, no 7, 1353-1369 (2016)
Pic 1 and 2 – NWA 757 main mass in different side views
Pic 3 to 5 – NWA 757 close view of wide shock veins, 8 x 6 mm each
Main mass, 571.5 g
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