Could be old-growth pine. We took down an old corn crib a few years
ago. Beautiful wood.
We sanded it down and removed all the nails so that it could be resawed
on a bandsaw without ruining the blade. Made some wonderful bookcases
in the church pastor's office.

Tom Gardner nospam wrote:
I have a 100 + year old building that will be coming down. It has 10"x10"
posts on 8'x12' centers...hundreds of them. I don't know what species but
they are hard as rock. Is it worth trying to find out what they are, find a
market and salvage these?