Q: I'd like to know the differences in environmental impact between mined diamonds and those that are lab-created. Besides the obvious social upsides (avoiding war-torn producer countries, child labor in mines, etc.), what are the environmental benefits?

Asked by Gordon Haupt, MS ’91, PhD ’96, Oakland, Calif.

As most soon-to-be engaged men can tell you, you have to consider the "four Cs"—carat, color, clarity and cut—when buying a diamond. It's complicated enough without "conscience" and "carbon" in the mix. My now-wife and I went ring shopping together about a year-and-a-half ago. Concerned about all six Cs, we (well, really she) chose a Canadian diamond in a recycled platinum setting. While we did not consider lab-created diamonds, they are becoming a viable alternative to natural gems, and they have a smaller environmental impact.

Scientists can now make gem-quality diamonds that are chemically identical to natural ones. To replicate the high-pressure, high-temperature environment that produces diamonds in nature, Florida-based Gemesis uses 20 kWh of energy to create each carat of synthetic stone. In Florida, that amount of energy produces about 26 pounds of carbon dioxide emissions—approximately what would be emitted by driving a car 36 miles to pick up a conventional diamond at a suburban discounter.

I did a quick calculation (see Nitty Gritty) for the Ekati diamond mine, which has been nationally recognized in Canada for its emissions reductions. The mine's operations create 143 pounds of carbon dioxide emissions per carat mined—five-and-a-half times what it takes to make synthetic diamonds.

Mining's impacts go way beyond greenhouse gas emissions. The emissions from producing a one-carat mined diamond are less than 10 percent of those from flying roundtrip from New York to Cancun for your honeymoon. But diamond mining also involves clearing land, and it produces liquid and solid wastes that can pollute ecosystems and destroy habitats, a particular concern in fragile environments like Canada's arctic tundra, and the tropical forests of Africa where unregulated mining can poison people and ecosystems alike. Synthetic diamonds do not have any such ecosystem- or habitat-related problems.

Lab-created diamonds also avoid the social downsides of some mined diamonds. Diamonds' high value and small size has led to the unregulated mining and smuggling of "conflict diamonds," which have been used to fund brutal wars in Africa, as depicted in the movie Blood Diamond. World diamond trading nations have certified conflict-free diamonds since 2003, but the ease with which diamonds can be smuggled means that there is still a chance that any natural diamond you buy has unscrupulous origins.

Synthetic diamonds also typically cost 15-30 percent less than equivalent natural stones. Yet, before you rush out and buy yourself some lab-created bling, you should know that "white" or colorless lab-created diamonds only come in sizes smaller than one carat. That's certainly big enough for many fiancées-to-be, but (ahem) some customers are more demanding.

As an alternative, you could ask your grandma for her diamond jewelry, should she be lucky enough to have any. With a family heirloom or any secondhand diamond, you'd save the environmental impacts associated with mining or lab-creating a new diamond, in addition to those from mining more gold, silver or platinum (all of which are environmentally destructive processes) for the setting.

Remember, even lab-created diamonds are forever. So, regardless of the type of diamond you choose today, you can reduce the environmental impact of the world diamond trade by passing your diamond on to someone else when you no longer wear it regularly.

Andy Martin, ’02, plans to receive his MBA and master's in earth sciences in 2010, and develops residential energy management tools for a start-up in New York City.