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
Theory of forms admitted were impossible to know. Nevertheless, he formulated a very specific description of that world, which did not match his metaphysical principles. Corresponding to the world of Forms is our world, that of the shadows, an imitation of the real one. Just as shadows exist only because of the light of a fire, our world exists as, "the offspring of the good". Our world is modeled after the patterns of the Forms. The function of humans in our world is therefore to imitate the ideal world as much as possible which, importantly, includes imitating the good, i.e. acting morally. Plato