Jadeite is one of two varieties of the species jade, the other one being nephrite and although similar in appearance they have different chemical compositions. Jadeite is harder and denser than nephrite resulting in a finer polish, but nephrite is tougher due to a microscopically small fibrous interlocking structure. Jadeite still has an excellent toughness, but with a larger granular to fibrous interlocking structure.
The rarest and most expensive jade is called imperial jade, an emerald coloured jadeite from Myanmar (formerly known as Burma) it is opaque to translucent; although mainly translucent at the edges of the stone. The green colours of jadeite are generally brighter than those of nephrite, jadeite is also the rarer of the two and hence the most expensive. The stone is fashioned into cabochons, inlays, beads and ornamental objects.
Jade has a long history as a prized material; ancient artefacts made from jade include weaponry, armour, objects of adornment, religious and personal ornaments.
Sources locations for jadeite include: Canada, Guatemala, Myanmar, New Zealand, Russia and the USA (Alaska and California)
Natural jade is described using an A to C classification to determine the type of treatment, if any, it may have received.
A jade is natural jade that has not been treated. It may be polished using a wax that does not contain dye.
B jade is natural jade that has been treated with fillers, usually polymers to fill fractures and surface depressions.
C jade is natural jade that has been dyed or stained.
When jade is treated with fillers that contain dye it is termed B+C jade.
Before treatment by fillers, the material may have been bleached to remove stains caused by other minerals.
Jade simulants are made from porous minerals dyed to jade colours. When compared to natural jade they are quite convincing.
Genuine gemstone materials that are similar in appearance to jade are also used as simulants. For example, aventurine quartz, hydrogrossular garnet and bowenite have all been used to simulate jade.