Nephrite -- one of the November stones mascots
Our regular column “Stone mascot of the Month” features November nephrite -- a well-known semi-precious stone that is often used as ornamental material. Its colour varies from light grey to grass green, and can be yellow, blue and black. The name nephrite comes from ‘lapis nephriticus’, which in turn is derived from the Greek ‘λίθος νεφριτικός’, which means 'kidney stone' and is the Latin and Greek variant of the Spanish 'piedra de ijada' (from which the names 'jade' and 'jadeite' originate). Accordingly, nephrite was once considered a talisman that gave protection against kidney stones. Nephrite and jadeite were considered the same mineral until 1863. They share a composition dominated by calcium silicate with the addition of iron and calcium. "Jade" is the term that mineralogists consider acceptable to refer to both stones. Of the two, jadeite or "Chinese jade" is less common and more valued, although nephrite or "New Zealand jade" is also very popular as material suitable for carvings especially in China where jade minerals are rather expensive and especially revered.
Jadeite is harder and rarer than nephrite. Currently, Burma is the country that supplies 95% of the world's gem-quality jadeite.
Academician Alexander Fersman classified nephrite as a semi-precious stone of the first category. However, many scientists consider it precious. Although in European countries and the United States, diamonds, rubies, sapphires, emeralds, opals, garnets and some other gemstones are much more popular than nephrite and jade. Jade is not considered so valuable in these regions, unlike in China where it is considered a stone of national significance.
In the 18th century, after the trade agreement was signed between Burma (Myanmar, since 1989) and China, jadeite was flooded into China. The members of the imperial dynasty soon appreciated it. Chinese artisans always distinguished jadeite from nephrite, and valued much more for jadeite. Nevertheless, in modern publications, despite the well-defined difference between nephrite and jadeite in terms of chemical composition, hardness, light refraction and price (jadeite is much more expensive) a certain confusion persists.
Jade was widely known and used in processed form as early as the Bronze Age*. At that time, it was considered the most durable stone, which was preferred for making weapons, tools, amulets and talismans and figurines of the gods. Some items are known to have been made during the Neolithic period.
The ancient Egyptian priests associated the mineral with magic and power in the earth and underworlds. In the Muslim East, nephrite was considered the stone of victory, used for inlaying weapons, in particular for making sturdy handles for daggers, and for decorating knives and shields. Later, nephrite was used to decorate clothing.
In China, there is a statue of Buddha, which reaches up to 6 m in height and is made of precious white jade. In Samarkand, there is a tombstone that covers the tomb of Tamerlane in the Gur-e-Amir Mausoleum. Its uniqueness is that it is made of dark green nephrite; this piece is considered the largest in the world of such rare coloured stone. Tamerlane's grandson Ulugh Beg brought the tombstone from China.
As it has already been noted, the Chinese practically did not use jadeite until the 18th century. All ancient carved items in Celestial Empire were made of jadeite: famous spheres arranged one inside another, exquisite vases, bowls, goblets, caskets, animal figurines and pagodas. Jade was so highly valued in China that it was used to make plaques that were as valuable as coins, and paired jade plates served as passports for imperial envoys. Other cult objects were also made of jade. Academician A.E. Fersman called jade "the national stone of China". It is iconized there, and its useful properties are equated with the best qualities of human character: courage, patience and compassion.
Nephrite might be not only of green color, although most highly valued is the mineral of this color. Different deposits present people with nephrite of whitish tone, grey with veins and coloured spots, inhomogeneous black, yellowish-brown and even blurred blue shades. Nephrite is quarried on all five continents. In Russia, its deposits are in the Urals. The largest deposits are in China, New Zealand, Canada, Kazakhstan and the USA.
*The Bronze Age is an epoch in human history (XXXV/XXIII - XIII / XI centuries B.C.) distinguished based on archaeological data, characterized by the leading role of bronze products.
Kornilov N.I., Solodova Y.P. Jewellery stones - 2nd edition, Moscow; Nedra, 1986