Two different gem materials can correctly be called jade. Jadeite is one of them, and the other is nephrite. Both are actually metamorphic rocks made up of tiny interlocking mineral crystals. These interlocking crystals make both gems exceptionally tough. Jadeite comes in a wide range of attractive colours: Many shades of green, yellow and reddish orange, plus white, grey, black, brown and lavender (often a light purple or light greyish violet colour). The colouration is often streaked or mottled, giving jadeite gemstones an interesting visual texture that carvers can use to create imaginative and intriguing effects.
Jadeite jade comes in a variety of colours. Green is the most valuable. - Courtesy Mason-Kay Fine Jade Jewelry
Nephrite is also accepted as jade in the international gem and jewellery industry. It ranges from translucent to opaque and can be light to dark green, yellow, brown, black, grey or white. Its colours tend to be more muted than jadeite’s, and they’re often mottled or streaked.
Modern gemmologists use the word “jade” as a generic term for both nephrite and jadeite. These gems have been linked throughout history. In fact, the term jade has also been applied to a number of gems and ornamental materials that resemble jade, and even some man-made equivalents resembling jadeite and nephrite.
Rough jadeite jade often takes the form of boulders. This one from Myanmar weighs 23 tonnes.