Jade

A greenish black to creamy white ornamental stone or gemstone, highly valued in China and Korea.

Translucent emerald-green fei cui jade (known traditionally as 'jadeite jade' but this name is misleading as not all of this jade is mineralogically jadeite) is the most prized variety. Rarely also blue, lavender-mauve, black, red or yellow in colour, depending on mineralogy and impurity elements.

In 1863, French mineralogist Alexis Damour discovered that what at the time was being called jade, were in fact 2 distinct mineral species, namely jadeite and nephrite.

Many different rocks and minerals have been marketed as jade, especially jadeite, nephrite and serpentine, but also green quartz, vesuvianite (californite), carbonates (carbonate jade), Hornfels etc. Gemmologists, however, usually restrict the name to just jadeite and nephrite, both characteristically forming very tough, fine grained rocks. Nephrite is much more common than jadeite, and is a tremolite and/or actinolite-rich rock, and this is why it has been classified here as a type of metamorphic rock rather than a generic term.

Jade from Myanmar has been divided into five groups according to the main mineral constituent of the respective sample (Franz et al., 2014): (1) jadeitites with kosmochlor and clinoamphibole, (2) jadeitites with clinoamphibole, (3) albite-bearing jadeitites, (4) almost pure jadeitites and (5) omphacitites.