I found Blood Diamond, despite its occasional descent into cloying melodrama, to be a reasonably entertaining flick. But one of its central messages was pretty interesting: the culture of sophisticated, bourgeois Westerners who insist on fancy diamond engagement rings carries a price of bloodshed and misery half a world away.

The movie makes much of the fact that the World Diamond Congress has since adopted a certification process intended to reduce the traffic of "conflict diamonds". But any undergraduate could tell you that because diamonds are, for the most part, fungible, this certification scheme is likely to be largely ineffective.

The problems here are complex, resulting from a feedback loop of unstable, kleptocratic regimes propped up by the West's insatiable demand for diamonds. The regimes and militias who benefit from the diamond trade create conditions which keep these regions unstable, poor and thus reliant upon the trade. Economists have long noted the counterintuitive point that countries with valuable natural resources often remain poor because the near-term incentive to steal overwhelms the incentive to maintain stable property rights necessary for a prosperous economy.

Over the long term, in order to be successful, African nations will need responsible, pluralistic governments which secure property rights under the rule of law. I would submit that one way to encourage such a transformation would be for Westerners to lower our "addiction to diamonds" (to adapt a familiar cliché normally used in a different context).

Which leads to the interesting question: why does our culture traditionally value diamonds as engagement gifts? I submit that a pricey engagement ring serves two important purposes:

• First, it acts as a powerful signal of fidelity and commitment. Evolutionary psychology teaches us that a mammalian female needs to be very discerning in her choice of sexual partner, due to the time, effort and risk involved in pregnancy. The purchase of an expensive diamond is an efficient way for a male to credibly demonstrate his "fitness" in terms of commitment.
• Second, a diamond is a subtle way for a male to communicate his superior status, both to his prospective bride and to his sexual rivals. Social status is a key marker of fitness for male primates.

So the problem here is to find an alternative mechanism which conveys both commitment and status, while having no negative external social impact (or, better yet, creating a net external social benefit).

I submit a sort of public, web-based registry which publishes the names of the purchaser and recipient of a "donation diamond". Imagine you are an attorney making $150,000 a year, and you want to propose to your sweetheart. Using the "two months salary" rule, you would contribute $25,000 to your favourite 501(c)3 charity, and keeping a receipt for your year-end tax return, you would e-mail a copy of this receipt to the Donation Diamond registry. Having confirmed that this is indeed a legitimate charity, the registry would publish on its searchable web database your name as purchaser, your fiancee's name as recipient, and a "karat" number (say, $5,000 per karat) based on the magnitude of your donation. You could even have an index which translates this karat value into a "number of children saved from malaria", etc. This way, gossips and busybodies (i.e. her girlfriends) could evaluate the level of your commitment to her with a few keystrokes. It would be a nice symmetry if people chose to contribute to African charities, but I propose that one should leave this choice at the donor's discretion.

This solution has several benefits:

• It would adequately convey the groom's commitment.
• A larger donation would be a means to convey status.
• The charitable donation, if properly executed, will hopefully help someone in need.
  
• Tax-advantaged giving would provide more bang for one's buck.
• Last, but not least, it would give smug people a chance to show how socially responsible they are. In some social circles this carries a cachet of its own.
  

I would like to think my proposed solution would appeal to the cultural elites on both coasts, who tend be vocal in their professed dedication to social justice. The cynic in me fears that their love for baubles and trinkets may trump such dedication, which is why I think the last point above is important - social pressure would shame those who prefer blood diamonds to charity.

Questions:
Have I framed the problem correctly? Did I miss any other functions currently served by the institution of engagement ring purchase? Does my proposed solution have any glaring flaws? Can you perhaps think of a better solution?