by Nordor » Fri Sep 12, 2014 8:59 am
Although I lack the meteorite knowledge of the other respondents, from my archaeological experience I agree with the pot boiler identification. The excellent photos appear to show a typical piece of calcined flint, ie flint which has been heated to a high temperature and plunged into water to heat it. The crackling of the stone being typical evidence of stress fractures caused by the thermal shock. The grey colour of the flint is also typical as is the spalling on the surface where cracked stone separates and fall off.
In the Neolithic and Bronze age periods, pottery was generally too fragile to be placed directly on an open fire so the pot-boiler method was adopted and used extensively, as finds such as yours demonstrate. By the Iron Age, vessels were of much better quality and metal was available.
If you found the stone in-situ, it might indicate the presence of an ancient occupation site and local archaeologists or museums would be interested to hear about it. I note the word Wiltshire in you UN. that might be significant!
Hope this helps.