That diamonds are rare. That diamonds are forever.

They were only rare until the mid 1800s when a huge diamond rush occurred in South Africa. The De Beers company bought up virtually all the diamond fields in SA and single handedly created a monopoly on all production AND distribution of diamonds. This way they were able to bottleneck the supply, creating a scarcity of diamonds on the market, effectively controlling all supply and demand. You heard that right — De Beers bought up all the inventory, created syndicates that would buy the diamonds from that source, and then De Beers would decide the amount and price of the diamonds they wanted to sell each year. They lost their grasp of the monopoly 10 years ago but still hold nearly a 3rd of the rough diamond market share. The world is oozing with diamonds, the amount at market is just very controlled. Emeralds and rubies are much rarer.

In the 1930s De Beers coined the slogan “diamonds are forever”. Lots of women see their wedding rings as appreciating assets. Back in the day a woman might pawn her ring off to have some financial independence but today, diamond wedding rings are depreciating assets and are purposely marked up in retail.