GUBELIN - GEM LAB - Jade

中文  

Jade

 
Jewel of Heaven

History
Jade has a long and revered history in its usage by mankind. Worked by the Chinese since the Neolithic period, its legendary toughness has allowed it to be employed in the widest range of purposes.  Its beauty encouraged decorative objects, such as jewellery, amulets and carvings, while its physical properties and rarity promoted ceremonial, ritual and utilitarian functions, such as knives, daggers and even sceptres.  The Chinese belief in jade as a link between the physical and spiritual worlds meant that it was an intrinsic part of burials of the imperial family, and in ancient texts, was directly referred to as an aid to immortality. It has been, and still is today, so highly valued that it is known as the 'Stone of Heaven'.

The European etymology of ‘jade’ derives from the Spanish term ‘piedra de ijada’, or ‘loin stone’, due to a belief in its curative properties for the loin and kidneys. The Latin translation of this term, ‘lapis nephriticus’, suitably led to the name ‘nephrite’.  This Spanish terminology was due to the great value placed in jade by the Mayas and Aztecs of Central America.  However, it was in China that jade originally gained its great reputation and significance. Known as ‘yü’, the word for jade may also be translated as ‘precious stone’, and is one of the oldest in the Chinese language.  

Its pictograph was known as early as 3000 BC, at the time of the transition from knotted cords to written signs. In Chinese art this ‘precious stone’, yü, is the earthly embodiment of the cosmic principle which regulates the spiritual, ethical, and social morals in life. Writing circa 500 BC, Confucius attributed eleven virtues to jade, each associated with a physical property of the stone: loyalty for its colour, sincerity for transparency, for example. Today, jade is still greatly appreciated for its cultural connections, as much as its aesthetic qualities.

Gemmological Properties
The name ‘jade’ is a generic term applied to two different materials:  jadeite and nephrite.  Initially they were grouped together, due to very similar appearance and characteristics.  Both also have a tough microcrystalline interlocking structure, but, as was finally discovered in the 19th century, differing chemical compositions. While nephrite is a silicate of the amphibole mineral series tremolite-actinolite, jadeite is a sodium and aluminium rich silicate within the pyroxene group. Jadeite is also slightly harder, tougher and rarer than nephrite, making it the more valuable of the two.  

Omphacite Jade
Many historic jade items consist, fully or partly, of omphacite, which belongs to the same group of minerals (pyroxenes) as jadeite, grows in the same crystal system and has similar causes of colour. In addition to their mineralogical and chemical affinities, their appearances are very similar, too: both minerals form dense, solid aggregates of closely interlocked crystals yielding the supreme toughness jade is known for. Distinguishing omphacite from jadeite calls for sophisticated analytical equipment; moreover, the two minerals on occasion merge to form rocks, making the identification of a single mineral futile. For these reasons, Gubelin Gem Lab has decided to consider omphacite a type of jade alongside jadeite and nephrite, the two minerals already broadly recognised as jade.

Colour
Precious translucent jade occurs in a variety of delicate colours. Jadeite, specifically, can range from white, pink, lavender to black, but it is the green variety that is perhaps the most well-known and valued. Various green shades are created by the substitution of iron impurities within the structure, but the presence of traces of chromium produce the finest and most valuable ‘Imperial’ Jade:  a deeply saturated emerald green colour, and evenly translucent to transparent. The Chinese name fei-cui, or fei-t’sui, translates as kingfisher feathers, and used to refer to the green of the finest examples of jadeite. Today, however, the term fei-cui comprises all colours and qualities of jade and related materials. In the late Qing Dynasty, Empress Dowager Cixi was the one who loved the semi-transparent and saturated green jadeite, which became known then as ‘imperial jade’ and started to use it as jewellery.

Mining Areas
Jade deposits are found in many parts of the world - in California, Guatemala, Italy, Japan, and Russia. Burma (Myanmar), however, is the recognised source for the finest material, and the Hpakan-Tawmaw jade tract - also known as Kyaukseinmyo, meaning 'Jade Land' - in the northern Kachin state, the main producer. Although Burmese jadeite was only relatively lately introduced into China – until 300 years ago, the majority of Chinese jade was nephrite – it is Burmese jadeite that has gained and retained the highest distinction. Both the quality of the material, as well as the remoteness of the mines, have created an aura of mystery and respect around jadeite from Burma.

Download Booklet
Gübelin Gem Lab Jadebooklet



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