Scientists are appealing for help to trace fragments of a meteorite.
The space rock is believed to have landed somewhere near Shrewsbury, Shropshire, after being spotted over the county on Wednesday.
Members of the UK Fireball Alliance, spent the bank holiday searching for pieces, but none have been recovered and they are appealing for help.
Prof Katie Joy said the rock would be a glossy black or brown colour, and about the size of an Easter egg.
The alliance, a collaboration between academics and citizen scientists interested in meteor observation and meteorite recovery, has appealed to the community for help tracing it.
Dr Luke Daly of the University of Glasgow said about 500g (1.1lb) of meteorite is believed to have landed on the ground in roughly four fragments south of the county town.
“Given the amount of wheat and oilseed rape in the area, we have been literally looking for a needle in a haystack,” he said.
Prof Joy, from the Department of Earth and Environmental Sciences at Manchester University added: “The meteorite won’t be hot and is as safe to handle as any other rock, but please don’t pick it up with your bare hands as that would contaminate the stone.
“It’s probably a glossy black or brown colour, maybe with the dark crust broken off in places.
“The largest pieces won’t be bigger than an Easter egg, and the smallest could be the size of a mini egg.
“It may be in a place where rocks aren’t usually found, like on a lawn or footpath.”
She urged people not to take risks while searching, but said scientists would be happy to look at any discoveries of objects which seem “out-of-place”.