What don't you get?????? I think I have asked this question of you before. If you don't understand then learn.
The short rule is: value of a something is what someone is willing to pay for it and sometimes it makes no sense to many why it's valued as it is. One could say that in comparison, there are many modern silver coins and medals (or even the spot price of 1 oz silver) that are under valued and this might not be true if we apply the above rule. The value we assign to anything made from silver is 100% subjective. Some people won't buy silver at USD $18/oz because they feel that this price is too high. Others (mainly those who were buying when the spot was above $36) feel it's a steal. And still others wouldn't buy silver if the London fix brought it down to USD $.5/ oz. The value of silver is entirely subjective. .
Well the bid is more like $750. Dolomite is in the US. Was entertaining watching the 'bar wars' back when we were at dollar for dollar on the exchange rate. And heck if you have the money and want it bid what ever you like. Sets a nice precedent for those lucky enough to dig one of these up.