Nephrite in the context of "Stone carving"

The Steppe Route was an ancient overland route through the Eurasian Steppe that was an active precursor of the Silk Road. Silk and horses were traded as key commodities; secondary trade included furs, weapons, musical instruments, precious stones (turquoise, lapis lazuli, agate, nephrite) and jewels. This route extended for approximately 10,000 km (6,200 mi). Trans-Eurasian trade through the Steppe Route preceded the conventional date for the origins of the Silk Road by at least two millennia.

Jade is an umbrella term for two different types of decorative rocks used for jewelry or ornaments. Jade is often referred to by either of two different silicate mineral names: nephrite (a silicate of calcium and magnesium in the amphibole group of minerals), or jadeite (a silicate of sodium and aluminum in the pyroxene group of minerals). Nephrite is typically green, although may be yellow, white or black. Jadeite varies from white or near-colorless, through various shades of green (including an emerald green, termed 'imperial'), to lavender, yellow, orange, brown and black. Rarely it may be blue.Both of these names refer to their use as gemstones, and each has a mineralogically more specific name. Both the amphibole jade (nephrite) and pyroxene jade are mineral aggregates (rocks) rather than mineral species.

Nephrite was deprecated by the International Mineralogical Association as a mineral species name in 1978 (replaced by tremolite). The name "nephrite" is mineralogically correct for referring to the rock. Jadeite is a legitimate mineral species, differing from the pyroxene jade rock. In China, the name jadeite has been replaced with fei cui, the traditional Chinese name for this gem that was in use long before Damour created the name in 1863.

The Kingdom of Khotan, also called the Kingdom of Yutian, was an ancient Buddhist Saka kingdom located on the branch of the Silk Road that ran along the southern edge of the Taklamakan Desert in the Tarim Basin (modern-day Xinjiang, China). The ancient capital was originally sited to the west of modern-day Hotan at Yotkan. From the Han dynasty until at least the Tang dynasty it was known in Chinese as Yutian. This largely Buddhist kingdom existed for over a thousand years until it was conquered by the Muslim Kara-Khanid Khanate in 1006, during the Islamization and Turkicization of Xinjiang.

Built on an oasis, Khotan's mulberry groves allowed the production and export of silk and carpets, in addition to the city's other major products such as its famous nephrite jade and pottery. Despite being a significant city on the Silk Road as well as a notable source of jade for ancient China, Khotan itself is relatively small – the circumference of the ancient city of Khotan at Yōtkan was about 2.5 to 3.2 km (1.6 to 2.0 mi). Much of the archaeological evidence of the ancient city of Khotan however had been obliterated due to centuries of treasure hunting by local people.

Chinese jade refers to the jade mined or carved in China from the Neolithic onward. It is the primary hardstone of Chinese sculpture. Although deep and bright green jadeite is better known in Europe, for most of China's history, jade has come in a variety of colors and white "mutton-fat" nephrite was the most highly praised and prized. Native sources in Henan and along the Yangtze were exploited since prehistoric times and have largely been exhausted; most Chinese jade today is extracted from the northwestern province of Xinjiang.

Jade was prized for its hardness, durability, musical qualities, and beauty. In particular, its subtle, translucent colors and protective qualities caused it to become associated with Chinese conceptions of the soul and immortality. With gold, it was considered to be a symbol of heaven. Jade production began in China over seven millennia ago (c. 5000 BCE), yielding the largest body of intricately crafted jade artifacts created by any single civilization. A prominent early use was the crafting of the Six Ritual Jades, found since the 3rd-millennium BCE Liangzhu culture: the bi, the cong, the huang, the hu, the gui, and the zhang. Since the meanings of these shapes were not mentioned prior to the eastern Zhou dynasty, by the time of the composition of the Rites of Zhou, they were thought to represent the sky, the earth, and the four directions. By the Han dynasty, the royal family and prominent lords were buried entirely ensheathed in jade burial suits sewn in gold thread, on the idea that it would preserve the body and the souls attached to it. Jade was also thought to combat fatigue in the living. The Han also greatly improved prior artistic treatment of jade.

Tremolite is a member of the amphibole group of silicate minerals with composition Ca₂(Mg_5.0-4.5Fe_0.0-0.5)Si₈O₂₂(OH)₂. Tremolite forms by metamorphism of sediments rich in dolomite and quartz, and occurs in two distinct forms, crystals and fibers. Tremolite forms a series with actinolite and ferro-actinolite. Pure magnesium tremolite is creamy-white, but the color grades to dark green with increasing iron content. It has a hardness on Mohs scale of 5 to 6. Nephrite, one of the two minerals known as the gemstone jade, is a green crystalline variety of tremolite.

The fibrous form of tremolite is one of the six recognised types of asbestos. Inhaling asbestiform tremolite can lead to asbestosis, lung cancer and both pleural and malignant mesothelioma. Fibrous tremolite is sometimes found as a contaminant in vermiculite, chrysotile (itself a type of asbestos), and talc.