13:16 17 October 2013
A half-tonne meteorite, which scientists said is the largest fragment yet found, plunged into Lake Chebarkul in central Russia on February 15 and left a 6m-wide hole in the ice. It has now been recovered.
Live footage showed a group of people pulling out a 1.5 metre-long rock from the lake, which they placed on top of a scale for weighing. However, the rock broke up into three large pieces as it was lifted from the ground.
Dr Caroline Smith, curator of meteorites at London's Natural History Museum, "Fusion crust forms as the meteoroid is travelling through the atmosphere as a fireball.
"The outer surface gets so hot it melts the rock to form a dark, glassy surface crust which we term a fusion crust. Regmaglypts are the indentations, that look a bit like thumbprints, also seen on the surface of the meteorite."
Meanwhile, Sergey Zamozdra, an associate professor at Chelyabinsk State University, told the Interfax news agency: "The preliminary examination... shows that this is really a fraction of the Chelyabinsk meteorite.
"This chunk is most probably one of the top 10 biggest meteorite fragments ever found."