John Gunther

The price of diamonds can vary greatly depending on size, cut, color, and other factors, including whether they have a history. But because of the rarity of blue boron diamonds, they often fetch more money than gems of similar quality.

If your appraisal comes back too low - you don't have at least 10% equity for a conforming loan or 20% for a jumbo loan - you might not be able to refinance at all, at least with a loan that's packaged and sold to Fannie Mae and Freddie Mac. That means you may have to pay a much higher rate.