The two minerals nephrite and jadeite, popularly comprised under the name jade, belong to the hardest and most cherished materials of which primitive man availed himself in shaping his chisels, hatchets, ornaments, amulets and many other implements. Such objects, partially of considerable antiquity, have been found in many parts of the world--in Asia, New Zealand, in prehistoric Europe and America. The geographical areas occupied by nephrite are so extended that it may almost be classified with flint as one of those mineral substances utilized to a large extent by a great number of peoples. Since the localities where nephrite occurs in nature seem to be difficult to discover, and since nephrite was known for a long time as coming only from Asia and New Zealand, and jadeite merely from certain districts of Asia, the scientific world was being held in long suspense by what is known as the nephrite question. -- Introduction.