A “purple and crimson” diamond is being touted as “the world’s most valuable natural object in existence, on a weight to weight basis.” Its owner, who probably did not expect such a brouhaha over the gem, took it out for appraisal and it was subsequently publicized. Crimson diamonds have been discovered before, but no purple ones are known to exist. This one is between two and five carats, the jeweler won’t say exactly. If the owner is intending to sell it, perhaps the publicity is welcome.