Honestly? I think there's a bit of unintentional greenwashing going on.
By its very nature, anything you are physically putting out into the world can't be called sustainable. Don't get me wrong, I'm very conscious about how I create and with what materials. I don't plate jewellery as there are a lot of chemicals used in the process, I use only solid recycled silver and gold and try my best to limit waste.
All scrap is melted down and reused, and my packaging is FCS-approved. Does that make me a sustainable jeweller? I don't know.
I source my gemstones from a reputable supplier in Hatton Garden, London but gemstones often change hands tens of times from the mines to the cutters, before they land with the suppliers. There comes a point where the trail runs dry, and honestly, anyone claiming to have full provenance of a gemstone (unless they've bought directly from the mine which is possible in some cases), it's questionable.
There's a fantastic Netflix documentary called 'Nothing lasts forever' which digs (quite literally) into the use of diamonds and the difficulty in applying provenance.
As an industry, most of us are doing our best, but some are being less than genuine. I can never claim with certainty my gemstones are ethically sourced but I try my best, which is why I prefer the term responsibly sourced. There is a debate for using lab-grown stones, but this also has its compromises and I do not believe taking away a country's largest industry is ethical either.
Would you be more likely to buy from a jeweller claiming to be sustainable without questioning their understanding of the term?
*This isn't to 'out' any jeweller using this term. Many do. But I think it's become a thrown-around word and can unfairly put companies at an advantage when their marketing implies they are sustainable without backing up their claims. (Spoiler alert, pretty much ALL the silver and gold we use is recycled)