Scientists have found that New Zealand pounamu is the toughest stone of its kind anywhere in the world, after running the first ever strength tests on samples of our famous green stone.
Researchers from the University of Otago and Earth Sciences New Zealand tested seven pieces of pounamu, working with Māori carvers and Te Rūnanga o Ngāi Tahu. The results, published this month, showed the stone was two to four times tougher than nephrite jade tested anywhere else in the world.
Pounamu, also known as nephrite jade, is a taonga, or treasure, for Ngāi Tahu. It is only found in Te Waipounamu, the South Island, and is prized by carvers for making tools, weapons and jewellery.
The team used special tests, including bending stone samples and studying them under powerful microscopes, to learn why pounamu is so hard to break. They discovered that the toughest pieces were also the ones that carvers, using nothing but their own experience, had already picked out as the best for carving.
Dr Simon Cox, from Earth Sciences New Zealand, said the findings backed up generations of traditional knowledge. “Māori have known for centuries that good pounamu is incredibly difficult to break,” he said.
Paul Madgwick, chair of Te Rūnanga o Makaawhio, said the research would help with the ongoing work of protecting pounamu. “Learning everything we can about pounamu supports our kaitiakitanga of this precious material,” he said.
Scientists say there is still more to learn about exactly what makes pounamu so strong.
SMART Prep | Quick Question 
