It was when Danish jeweller Sarah Müllertz was working as an architect in the 2000s that she came across the foundations of a new future in the form of an extraordinary material: wood from the heart of the mpingo or African blackwood tree. A gnarly species that grows very slowly in Tanzania, the mpingo, most commonly used to make clarinets and oboes, has one of the hardest and most durable woods in the world, often completely black and with no discernible grain.
It’s a challenging material – so strong that it can blunt a machine cutter – and the architectural team eventually decided not to use it for their design objects. Yet Müllertz, whose father sourced wood from forests in east Asia during the 1970s and ’80s, remained fascinated by it. And so, while working for the award-winning Danish firm Henning Larsen on large-scale projects such as Moesgaard Museum in Aarhus, she also developed her own side project, Kinraden, a sustainable fine-jewellery collection made from recycled 18ct gold and sterling silver, using precious “stones” made from mpingo.
Polished to a velvety lustre and shaped into both organic forms and traditional diamond cuts, this enigmatic black wood is the punctuation mark in Kinraden’s graceful, minimalist designs. The pieces are simple but artful: single earrings that drop in fine gold chains; others that behave more like bangles, contouring the whole ear; the classic Kindred ring, with its stone of brilliant-cut mpingo. “I don’t believe in fashion when it comes to quality materials,” says Müllertz. “Gold is forever, whatever you do, so I’d rather go into classical shapes. This is old but new because the material makes it different.”
The brand recently collaborated with the Danish ready-to-wear designer Mark Kenly Domino Tan on Stilos, a limited-edition collection of earrings that made its catwalk debut at Tan’s autumn/winter ’20 show during Copenhagen Fashion Week. With oversized organic forms, like a teardrop or a pocket of gold, silver and mpingo, they are made to order (from £240).
Kinraden’s wood comes from forests in Tanzania, sustainably managed by the WWF, and Müllertz only uses off-cuts from the production of wind instruments, sourced through an organisation in London called Sound and Fair. “When I started out in 2014, people thought I was really strange to use wood,” she says of the brand, which has been set up as a circular business. “The necessity and urgency of preventing climate change wasn’t that present five years ago.”
Accessible supplies of gold and silver for mining are finite – so Müllertz has chosen certified recycled gold and silver rather than sustainably mined metals. “I don’t believe we should take any more natural resources from the earth,” she says, apologetic for the fact that the pre-owned metals she sources still have to undergo a chemical process to extract them from anything else they may have been blended with. “But then I don’t add anything to it afterwards,” she says. “That makes it a little softer than normal 18ct gold, but I want every material I send out into the world to be as pure as possible so that it can be recycled again.”
It’s an idea that she has taken with her from the building industry, where there has been much discussion about how to construct buildings from materials that can be disassembled for reuse. “We need to think in a completely different way about what we design and make,” she says. “We need to be smarter and reuse the things we already have.”
When she started out, she took the wood to European diamond cutters, but was turned away. No one wanted to handle it. “The craftsmanship is difficult because the design is so simple,” she says. “You can see the flaws very easily if they appear.” Eventually, she found a female-owned workshop in Bangkok, highly skilled and excited to work with the wood.
But it took a long time, and an inquiry as to whether anyone else is using mpingo for jewellery is greeted with a laugh. “What we are doing is so hard, I don’t think anyone else would want to do it.”