Jade consists of two different metamorphic mineral assemblages: jadeite jade and nephrite jade.
The green colour for which jadeite jade is most famous (‘Feicui’) comes from traces of chromium in the matrix. Other colours of jadeite include white, brown, lavender, black and grey. Jadeite jade is often treated and thus separated into three categories: A jadeite jade (untreated), B jadeite jade (bleached and impregnated) and C jadeite jade (bleached, impregnated and dyed). Known since Mesoamerican times from Guatemala, today the main and most important source is the mines in Kachin State in Upper Burma (Myanmar). The main market for jadeite jade is China.
Nephrite jade has already been used since prehistoric times as an ornamental stone in Europe. It is an important stone for Maoris in New Zealand, known there as pounamu. Main deposits today are located in Canada, Taiwan. Nephrite jade is often greenish to brown in colour, but also white and black. It can be distinguished from jadeite jade using a number of different gemmological methods.