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
Tensor product of quadratic forms from this that if we have diagonalizations of our quadratic forms (which is always possible if formula_9 is invertible) such that then the tensor product has diagonalization Tensor product of quadratic forms The tensor product of quadratic forms is most easily understood when one views the quadratic forms as "quadratic spaces". If "R" is a commutative ring where "2" is invertible, and if formula_1 and formula_2 are two quadratic spaces over "R", then their tensor product formula_3 is the quadratic space whose underlying "R"-module is the tensor product formula_4 of "R"-modules and whose quadratic form is the quadratic form associated