Why are engagement rings usually diamond?

When someone proposes marriage, tradition dictates that it should be two things: 1. A surprise, and 2. involve a beautiful engagement ring, usually diamond. It turns out 20th century advertising are behind both of these cultural expectations. Blame Don Draper for feeling the heat to pick out the biggest, sparkliest, and purest diamond for your future wife.

Specifically De Beers sold us all on the idea of the preciousness and romance of diamonds, and the important of a man surprising his lady with a creative and breathtaking proposal. At the time De Beers practically had a monopoly on diamonds, owning about 90% of the world’s supply. This sounds like a good deal, but diamonds had suffered a huge drop in value for decades. In 1870 massive diamond mines were discovered in South Africa near the Orange River. Diamonds were mined by the ton, which increased supply dramatically and lowered the overall value of the stones. To this day the resell value of diamonds are no where near the retail price you pay for them because the supply is still much larger than most people would expect. The engagement ring industry capitalized on this plummet in value by by attaching sentimentality the longterm bond of marriage to the jewelry.

De Beers advertisements advocated surprise proposals because it laid the burden of picking out a diamond on the man. When women helped shop for their rings, they usually went for the lower priced items, but in general, when men shopped alone they can be easily upsold because they don’t want to disappoint their future bride.

De Beers didn’t just pull the idea of a diamond engagement ring out of thin air, though. The first diamond engagement ring dates back to 1477 when Archduke Maximilian of Austria proposed to Mary of Burgundy with a ring made of diamonds in the shape of an “M.” Up until the late 1930s, though, diamond engagement rings were only considered a luxury item. De Beers’ “A diamond is forever” ad campaigns changed all that, and transformed the expectations of marriage proposals.