In the formula approach, this author emphasizes conservative estimates. This is obviously to protect you from disappointment and financial loss. On the other side of the coin, if you decide on an extremely conservative approach in your favor, you may look foolish when the diamond is removed from the mounting and weighed before the transaction is completed. You want to be very careful in taking your measurements to make absolutely sure there are not any errors. The safest way in buying mounted diamonds is to make contingent offers based on weight and grading insofar as the mounting allows. If the offer is not even close to the asking price, then there is no need to pursue the matter any further.