This is a great PBS Frontline from 1994 about the De Beers diamond cartel, and how that company has manipulated the availability of diamonds to create a false scarcity and keep prices high. It tells the story of a pretty wretched state of affairs. De Beers essentially defines the phrase “evil corporation.”
The thing is this: diamonds are not inherently scarce, and therefore not inherently valuable. This is a grand charade perpetuated quite effectively by De Beers. To be clear: the value of diamonds is purely a result of market manipulation, nothing more.
The key is the phrase towards the end:
After a century of maneuvers to control the supply and price of diamonds, the cartel’s greatest accomplishment may be that it has transformed the illusion that diamonds are valuable into a hard reality, and the future of the diamond empire may now rest with the complicity of millions of consumers all invested in the myth that diamonds will be valuable forever.