If it's J-Lo or Beyonce it's probably the real deal; if it's your cousin Joan, more likely it's a bit of old rhinestone. As with so much in life, the question of who else has it and the status they gain from it are what make a thing desirable.

The faultlines in the diamond trade have been showing for some time yet even a film like Blood Diamond seems incapable of stalling our global fetishising of these objects. Almost a month since Leonardo DiCaprio first hit American screens in this tale of diamond-funded conflict in 1990s Sierra Leone, diamond sales are on a record high.

Though the rocks may have come perilously close to becoming the new fur, a massive publicity campaign by the industry seems to be stemming the suggestion that there is still blood on them. On the face of it, the Kimberley process of certification may appear to have cleaned up the industry, but campaigners still assert that there are plenty of illegal diamonds on the market.

Yet even if the industry has cleaned up its act, there are other reasons to ditch the diamond. Few substances encapsulate our screwed-up relationship with money, status and value in quite the same way.

Take away all the myths and marketing around these bits of sparkle and you are left with a piece of rock.

And how many more of our possessions are like this?

That house you bought: wasn't half its charm the sense that other people valued its location and style, the sense that with it would come admiration? We live in a world in which value is rated only in terms of the perceptions of others, and where diamonds are clearly overrated.

It's no big secret that a diamond is not forever. It can be cracked, chipped, cut, shattered or incinerated. It is also not as rare as its price tag might imply. Since 1870, when huge diamond mines were discovered near the Orange river in South Africa, they've been just chips off a huge block. Diamonds produced in a lab are difficult to tell apart from their mined cousins.

However, clever marketing campaigns in 1940s America, which placed an emphasis on the gems as tokens of love and on the slogan "a diamond is forever" have all combined to give us a sense of the jewels as the ultimate representation of love and wealth. And how sad is a representation of love whose value is determined by the world's sense of its worth, rather than by a couple's intimately-shared values?