Nephrite "hei-tiki" (neck pendant). These are believed to have their own "mana", are handed down as valuable heirlooms, and often given as gifts to seal important agreements. It has also been used for a range of tools such as adzes, as Māori had no metal tools before European contact. Commonly called "greenstone", jade jewellery in Māori designs is widely popular with tourists. Stone is often imported from Canada, China and Siberia, and Ngai Tahu runs a pounamu certification scheme to verify the authenticity of New Zealand stone. Nephrite Nephrite is a variety of the calcium, magnesium, and iron-rich amphibole minerals tremolite
Ornamental turning Lukin "Ornamental Turning", by T D Walshaw, and "Holtzapffel Volume VI" by John F.Edwards, 2013. Reprints of all these books are usually obtainable. The Society of Ornamental Turners was founded in 1948 with the object to encourage, develop and promote the study and practice of the art and science of ornamental turning. Its members meet quarterly in London to display examples of their work, share their experiences and attend a lecture or demonstration. Seminars and outings to places of interest are also arranged. A bulletin containing articles on all aspects of ornamental turning and news of the society is published