Stone Mark-up

[abknight@zzzzzz]

I am staring down the barrel of a contract to commission
and I am wondering if there is an "industry standard"
mark-up the the carver adds to his price for the  quarry
stone.  It seems a mark-up might be in order given the
exposure the carver takes that the stone may have faults
that could undermine the carving or even require that he
purchase at his own expense a second stone.

I would appreciate any thoughts on this matter from any of
the active contractors or sellers of sculpture.

I am using the contract in the Tad Crawford book, Business
and Legal Forms for Artists.  It also has me somewhat
confused in that in one clause it states that time shall
not be considered of the essence and in another that if
the artist is 90 days late he returns all that he has been
paid, should the purchaser wish to terminate the
agreement.  Ouch!   Don't be late!

Thanks,

Bill