Sparkling, expensive, and wonderfully impractical, a piece of jewellery encrusted with diamonds is the ultimate indulgent Christmas gift. But as we become more aware of how so-called blood diamonds have funded bloody wars, genocide and caused the displacement of millions of people, shoppers are more interested in provenance than ever before.

And so the sourcing of diamonds is a hot topic in the jewellery industry. Shoppers are demanding to know where gemstones come from, the conditions they were produced under, and the social and environmental impact on local residents and habitats.

Some 42% of consumers want more information on whether the jewellery they are buying is ethically sourced, according to a 2017 report by the trends forecaster Mintel.

The horrors caused by blood diamonds first came to international attention in the late 1990s, when evidence emerged that the stones had played a major role in conflicts including the civil war in Angola and the conflict in the Central African Republic.

As a result, the Kimberley Process, an internationally recognised certification scheme, was introduced. But in 2014, an estimated $24million worth of diamonds were still being smuggled out of CAR, according to the UN. The diamond market also affects countries where they are processed, most notably India.

While diamonds were once highly sought after by collectors, demand has slowed in key markets including the US, China and the Middle East, which hasn't been helped by an abundant supply of the gemstones, the Business of Fashion reported last year. In 2015, prices dropped by almost a quarter.

So how can we buy diamonds for our loved ones without unwittingly funding misery? Lab-made synthetic diamonds are an option that have been rapidly growing in popularity, particularly among millennials. This has prompted the Diamond Producers Association to unveil its 'Real is rare. Real is a diamond' campaign.

But for those who are put off by fakes, stones described as conflict free are a good place to start. The Forevermark and the Canada Mark are among diamonds that are tracked from the source come accompanied by an authentication certificate Cata Rosca, owner of Lila's jewellers in London, tells IBTimes UK.

When enquiring about where a stone came from and how it got to the store, the shorter the supply chain the better, she adds.

"It is important to find a jeweller you trust and who has a good reputation and ask if they have any supporting material they can supply with the gemstone," she stresses. "Sometimes the stones come with a certificate indicating the source - this is the ideal case. Other times the jewellers have contacts with either reputable gem dealers or directly with small mining communities and they can offer details regarding the provenance. Trust is still prevalent in the trade."

Vintage stones are another consideration. While their origin may be unknown, Rosca argues it is neither ethical nor practical to waste the gems already on the market by only buying new. "It would add more pressure on the trade and without sound procedures for ensuring sustainability, it would simply encourage illegal mining and smuggling."

"Everything that is salvaged and recycled is considered an ethical option, even when it comes to gemstones, and it is supported as such by the Responsible Jewellery Council." These are generally, cheaper, too.

She adds: "Once the consumers know the risks involved and that there are ethical alternatives they are more likely to opt for them, especially if this is not making a huge impact on their wallet."