Diamonds are a cartel’s best friend

The Atlantic – Have You Ever Tried to Sell a Diamond?:

The magazine conducted another experiment to determine the extent to which larger diamonds appreciate in value over a one-year period. In 1970, it bought a 1.42 carat diamond for £745. In 1971, the highest offer it received for the same gem was £568. Rather than sell it at such an enormous loss, Watts decided to extend the experiment until 1974, when he again made the round of the jewelers in Hatton Garden to have it appraised. During this tour of the diamond district, Watts found that the diamond had mysteriously shrunk in weight to 1.04 carats. One of the jewelers had apparently switched diamonds during the appraisal. In that same year, Watts, undaunted, bought another diamond, this one 1.4 carats, from a reputable London dealer. He paid £2,595. A week later, he decided to sell it. The maximum offer he received was £1,000.

The article details the manipulations of market and sentiment involved in creating the modern market for diamonds.