Gold may be the most coveted of metals, and it's even more precious these days, with concerns about the strength of the global financial system pushing the world's de facto reserve currency up to about US$1,000 an ounce. But even at its current high value, the Chinese will never hold gold in the same esteem as they do jade. China's affinity for the smooth stone goes back a long way - to about 3400BC in fact, when tribes were digging up deposits in the Yangtze River Delta to fashion into everything from weapons to cooking implements. Probably initially prized for its hardness and resilience, its beauty soon saw the stone take on a more ceremonial role. Various myths about jade's mystical origins - some said it was fashioned by thunder and captured the force of the heavens, others that it was crystallised moonlight - encouraged artisans throughout China and what is now Korea to shape it into offerings, statuettes and pendants. Worship of the stone arguably reached its apex in jade burial suits: odd, robotic-looking contraptions comprising panels that were wired together to house the bodies of particularly wealthy Han noblemen. The suits were based on the by-then widespread belief that jade didn't just look good, but boasted magical abilities to ward off decay and disease. Its virtues were extolled by sages such as Confucius, who claimed it embodied wisdom, energy and truth to such an extent that it was as precious as 'the Tao itself'. The much-vaunted substance appeared everywhere, from the mouths of opium pipes (to prolong the longevity of the smoker) to dining implements (to transfer energy to the food) and the palms of politicians (jade talismans were said to help the holder through tricky negotiations). While jade liquor is no longer in fashion and few people cram jade pieces into the mouths of corpses any more, a healthy respect for the stone remains. Jade bracelets, which are believed to be effective in combatting rheumatism, are worn by many people to this day. All jade may be good but some types are better than others. In ancient China, the most common indigenous variety was nephrite, a calcium-rich mineral that can have a greenish tint but is nearly as often yellow, brown or milky white. Royals far preferred jadeite, which China began importing from Myanmar (Burma) in the early 19th century - but is also found in New Zealand, Russia and Canada. Gem-quality jadeite commonly comes in white or deep green but blue, crimson and black varieties have also been discovered. Thanks partially to Chinese demand, rare imperial green jade, a translucent stone that's been compared to fine emerald, is the most expensive gem in the world, worth more per gram than diamonds. But the Chinese are far from the only people to see the mineral as special. The English word 'jade' comes from the Spanish phrase piedra de ijada, or 'loin stone', so named because it was believed keeping a chunk of jade close prevented aches and pains in a highly sensitive part of the body. New Zealand's Maori consider jade a taonga, or 'treasure', and regularly worked it into necklaces and weapons. Jade was also one of the most important materials in the rituals of Mesoamerican peoples such as the Olmec and Maya. With so many civilisations holding jade in such high regard, maybe there is something to the many beliefs that surround it.