>>Weather its $40,000 or forty million. A book covered with gems and gems of any kind would be worth more that that.<<
Possibly. The problem is that if the book survives and can be recovered, it would have to be subjected to some very expensive and time consuming conservation efforts otherwise, it would soon disintigrate to mush and end up with a value of about zero, the gems notwithstanding. It's not for nothing that marine salvage is called a good way to make a very large fortune into a very small one.
Assuming you recover anything of value at all, by the time you get done paying all the bills and the taxman, you seldom end up with much and it's not unknown for a salvager/treasure hunter to end up owing money.