Diamonds and sustainability

When buying most things, it is often the case that you have to make the choice between quality, price and sustainability. What is high quality and sustainable is often more expensive and what is sustainable and cheaper is often lower quality.

Lab grown diamonds and gemstones are one of those rare things which are higher in quality, better priced and more sustainable than their mined alternatives.

But are lab diamonds actually more sustainable than mined equivalent or is this another case of greenwashing? There is a lot of misinformation out there and it can be difficult to find the source of truth.

The only difference between mined and lab grown diamonds or gemstones is how they are produced and that’s the main focus of this article.

A note when reporting ‘per carat’ measurements

The reports and sources used in the industry (and referenced in this article) normalise the data on a ‘per carat’ basis. E.g. On average, De Beers mines use 80.3kWH of energy to produce 1 carat of a mined diamond.

However, it is important to remember that carat is just a measure of weight — it does not consider the quality of the diamond and whether the diamond is fully intact. Ten 0.1-carat fragments of brown diamonds are entirely different from fully intact 1 carat of gem-quality diamonds.

Argyle mine in Australia produces one-third of the world’s supply of diamonds. It is often used by mined diamond sellers (especially in New Zealand) as an example of ‘clean and ethical diamond mining.’

They repeat that the Argyle mine only uses 7.5kWh of energy per carat of diamond mined, but what is missing is that 80% of the diamonds found in the Argyle mine are brown diamonds — which are near worthless in jewellery. This means the actual energy cost of finding 1 carat of an intact gem-quality diamond is much higher.

With lab diamonds, all the diamonds produced are gem-quality and created as whole diamonds (not small fragments), which are much more valuable. So comparing ‘per carat’ measurements between mined diamonds and lab diamonds is not an apple-to-apple comparison.

So when reading this article and other articles and reports on the sustainability of mined diamonds vs lab diamonds, keep in mind that the numbers used for mined diamond ‘per carat’ measurements are most likely understated compared to gem-quality lab diamonds.

How mined diamonds are made

Mined diamonds are formed deep inside the earth’s core where high pressure and high temperatures crystallise carbon atoms into diamonds over millions of years. These were then brought up to the surface through a series of massive volcanic eruptions that happened over hundreds of millions, or even billions of years ago. These eruptions caused rock formations called Kimberlite pipes, and these formations are where most of the world’s diamond production comes from.

Although nature did the hard part of creating and bringing these diamonds up to the surface, it’s the finding and digging them out of the earth that is devastating to the environment.

Diamonds are relatively small (millimetres) and Kimberlite pipes are quite large (hundreds of kilometres). To find and extract these tiny diamonds among the millions of tonnes of rock and dirt, diamond mines need to be large-scale operations that use lots of heavy machinery and labour.

The impact of large-scale diamond mining operations

These huge mining operations negatively impact all aspects of the planet from the ground they dig up, the waterways they poison to the air that we breathe.

Impact 1: Displacement of Earth

Diamond mining operations are enormous. To get an idea of the size, the Diamond Council of America estimates that 250 tonnes of earth is moved to produce 1 carat of polished diamond and there are 148 million carats of diamonds mined each year.

Even the richest diamond mine produces 1 part diamond to 40 million parts of waste rock. Some mines are so large that you can see the holes from space.

These mines aren’t created in open wastelands. Diamond miners dig where the diamonds are — whatever people, animals, and ecosystems were there before aren’t there after. According to the Leakey Foundation, miners are even threatening world heritage sites around the African continent in search of diamonds.

For example, in Canteen Kopje in South Africa’s Northern Cape Province, diamond miners began mining on a world heritage site which was also a tourist attraction that brought money in for locals. Luckily this was stopped before any damage was done after a huge response by research institutes.

But this is just one site of many. Researchers suggested that 2 millennia of early human history could be wiped out by diamond miners in a couple of weeks. The Leakey Foundation also suggests that archeological sites are lost every day due to diamond mining.

Impact 2: Acidification of waterways

According to the University of Waterloo, one of the biggest environmental impacts of a mine is the acidification of the local waterways surrounding it.

When large amounts of rock and dirt are displaced and broken down, specific minerals that were previously trapped underground are exposed to air and water. These minerals react with outside air and water which creates an acidic runoff (namely sulfuric acid, which is the same acid used in batteries, and is correlated with an increased risk (+64%) of lung disease) that leaches into local waterways.

This acidification has led to the death of vast amounts of aquatic life, introduced heavy metals into the food chain and has even been blamed for putting further pressure on endangered animal populations.

Once acid mine drainage starts, it cannot be stopped — it will go on for thousands of years. The only way to stop acid mine drainage from diamond mining is to stop them from creating new mines.

Impact 3: Carbon emissions

According to an independent industry report from Frost & Sullivan, mining operations create approximately 57,000 grams of CO2 per carat of mined diamond. To get a sense of this, the estimated amount of CO2 produced from global diamond mining is equal to 1.5 million cars running for a full year.

For reference lab diamonds are reported to produce 0.028 grams of CO2 per carat created.

Comparing the impact of Lab diamonds to their mined alternative

Lab diamonds are made by replicating the conditions found in nature inside sophisticated, high-tech labs.

Several diamond ‘seeds’ are placed inside a growing chamber which is pressurised and heated to 5,500°C. Carbon atoms are added to the chamber which under the high pressure and temperature form bonds with the carbon atoms on the diamond seeds.

Over a few weeks, the carbon atoms layer on top of each other and the raw diamonds are formed — just like in nature. These raw diamonds are then cut and polished in the exact same way as mined diamonds.

Because this process is a closed system inside high-tech laboratories, lab diamonds don’t need large-scale mining operations and the associated negative environmental impacts.

An independent report from Frost & Sullivan comparing the environmental impacts of lab diamonds to mined diamonds found that mined diamonds overall have more than seven times more negative environmental impact than lab diamonds.