Jade is a very rare ornamental stone. The term “jade” is applied to two metamorphic rocks composed of silicates and showing off-white to green colors. Rocks can be formed by:

a) Nephrite, which is composed of a matrix formed by fibrous capillary crystals tangles of an amphibole of the Tremolite (Ca-Mg)–Ferroactinolite Series (Ca-Mg-Fe). The middle term of this series is actinolite. The higher the content in iron, the greener the color of the mineral.

b) Jadeite is a pyroxene rich in Na and Al. The precious shape of jadeite is formed by a granular aggregate of jadeite crystals.

“Jade” was a term that was applied to ornamental stones that were brought to Europe from China and Central America. It was not until 1863 that French mineralogist Alexis Damour realized that the term “jade” was being applied to two different minerals, jadeite and nephrite. With the naked eye it is not possible to differentiate jadeite from nephrite. The English term “jade” comes from the French l’ejade and the Latin ilia, which, in turn, are derived from the Spanish piedra de ijada (1565), due to the stone’s reputation for curing diseases of the kidneys and lower back. Jadeite jade is rarer and more expensive than nephrite jade.

Its use is restricted to tools (axes, knives, weapons) and ornamental objects, due to its high hardness, similar to that of quartz. This hardness makes it difficult to saw, polish and make thin sections. With the advent of metals, jade had its use restricted to adornments, usually very expensive. Sometimes more expensive than gold. It has had, for millennia, an exceptional value.

In some regions, such as China, Korea, India, Burma, Canada, Central America and New Zealand, jade has a long tradition of exploration. In China, the search for jade has a history of 8,000 years. There is a plethora of details, information and images relating to jade in each of these regions. In Africa and South America, on the other hand, there are only scant records of jade.

Commercially there are 5 types of jade: Type A, Type B, Type C, Type B+C and Type D, referring to color, texture and “stabilization”, which consists of exposing jade to acids and bleaches, including or not an impregnation with polymers. Myanmar jade was divided into 5 categories: (a) cosmochlorine and clinoamphibole jadeitites, (b) clinoamphibole jadeitites, (c) albite jadeitites, (d) nearly pure jadeitites and (e) omphacites.

Jade fakes are very common. May be quartzite with fuchsite (a green chromium mica) or green-dyed sandstones or agates. Also vesuvianite and greenish minerals such as feldspars and diopside.