Early in Diamonds Are Forever, Sir Donald Munger asks 007 how far his expertise runs on the subject. Bond rattles off the cuff by saying they’re the “hardest substance found in nature, they cut glass, suggests marriage.” M gets the laugh with his reply, but the interesting part is what Bond leaves out. He never mentions what a diamond is worth the morning after you buy one. Fifty-odd years later, that is still the part nobody covers. Somewhere between picking a shape and picking a