It's not very common that a private company's marketing campaign goes viral. It's even rarer that one is able to push their brand into mainstream English vocabulary (read: Zamboni, Kleenex, Google etc). However placing your product at the center of societies most important social ritual? That's probably only been done once by a monopolist named De Beers, with the common mineral: Diamonds.
American males enter adulthood through a peculiar rite of passage - they spend most of their savings on a shiny piece of rock... Americans exchange diamond rings as part of the engagement process, because in 1938 De Beers decided that they would like us to. Prior to a stunningly successful marketing campaign 1938, Americans occasionally exchanged engagement rings, but wasn't a pervasive occurrence.
The De Beers marketing machine continued to churn out the hits. They circulated marketing materials suggesting, apropos of nothing, that a man should spend one month's salary on a diamond ring. It worked so well that De Beers arbitrarily decided to increase the suggestion to two months salary. That's why you think that you need to spend two month's salary on a ring - because the suppliers of the product said so.
Today, over 80% of women in the US receive diamond rings when they get engaged. The domination is complete.
The supply of diamonds is basically controlled by one company that in turn convinced everyone that what it was selling is valuable.
As a naive undergrad student I think it's weird how people shell out big money for diamonds and other jewelry. I understand things like fine wine and art, because of their rarity, but diamonds aren't rare and perfect stones can be synthesized nowadays. It seems like a product that is bought only because it is expensive.
Will you buy one if your significant other wanted it?