Real stone (portland or bath stone perhaps). Only includes the surround not the hearth which was cemented in place too firmly to survive removal. But the hearth is just square, not carved like the surround and surround could be used with a complementary hearth too of course as surround just stands on the hearth. Fire opening is standard size of 18in x 22in. Size is 45in wide, and 36in high with the hearth.
Note it came with house, the estate agents described it as minster fireplace, but it does look similar to current minster fireplaces (which cost near £2000 new).