God forbid people should know about their artificial scarcity.
Saw a documentary on PBS (of all places!) once about the DeBeers monopoly, and how they bribe, or do whatever they have to in order to maintain that monopoly, and to push the fairy tale that diamonds are either rare, or have any real value.
Why don’t jewelry stores sell used stuff? SURELY it could be cleaned up, and resold, right? That is, unless the diamonds really are mostly worthless trinkets marked up by a global monopoly.