Jade is the household name used to describe two silicate minerals: Jadeite and Nephrite. The difference between the two minerals was only discovered in 1863 by Alexis Damour. Both minerals have a similar crystal structure and corresponding colour variations: although they are not identical. Nephrite is slightly tougher than Jadeite, due to its more fibrous structure of interlocking crystals. Nephrite can range from an almost black dark green to a pale chalky mint green and can have a brown outer skin, weathered from the oxidation of iron. This discolouration is often utilised for dramatic visual effects by skilled carvers, although the colour contrast is not as dramatic as in two layered onyx or agate.
The interlocking crystal composition of both jadeite and nephrite, makes jade porous enough to be dyed. This is done to enhance the natural colour of jade used in jewellery. To enhance the green shades, yellow and blue pigments are inserted, but often fade swiftly, whereas an artificial enhancement of mauve jadeite can last longer. Jadeite has a broader colour range; from pure white, red, orange and mauve to blue and violent and the highly prized traditional emerald green shade known as Imperial Jade, is best associated with jade.
Jade deposits have been found across the globe, from China to California down to Australia and across parts of Africa. Like many hard-stones carved into amulets since antiquity, the stones themselves have become imbued with protective qualities. Jade has been a long standing material used to adorn the human body: Maori tribes in New Zealand carved pendants from jade, in early China, jade was known as ‘Yu’ or the Royal Gem, and carved into bangles, and in Europe in the 1920s-30s jade was embraced by Parisian jewellers such as Cartier for delicate Art Deco drop earrings.