I may be a little behind the 8-ball here, but I just learnt that engagement rings didn't always sparkle with rare, glittery diamonds. Instead, it used to be much less expensive coloured gemstones that filled the fourth-finger ring – until an advertising genius convinced the world that "diamonds are forever"...

"One of the biggest advertising ideas of the last century was the idea of using diamond rings for engagements. Precious stones were used in the Victorian era. But the idea that it had to be a diamond came from an advertising guy who worked for N.W. Ayer, who happened to be connected to the Oppenheimer family, of De Beers," explains Steve Hayden – the mastermind behind Apple Computer’s “1984″ ad, and vice chairman of Ogilvy & Mather Worldwide – in a 2005 news article.

"He had an idea: Let’s make the diamond ring the engagement ring of choice for the world. They started off with Anglophone countries, and then moved to Japan and China and everywhere else. It increased the value of that market billions of times."