Jade in Iran

part 2

Mineralogy and technology

The jade of objects that originated in Iran is nephrite. The mineral belongs to the tremolite-actinolite series of the amphibole family; it is slightly less hard than the quartzes (at 6 1/2 on Moh’s scale), but is extraordinarily tough due to the interlocking felt-like structure of its crystals (Webster, pp. 223-24). Like other hardstones, it is worked by drilling, grinding, sanding and polishing with grits and powders, typically harder than itself and delivered on, or as a component of, mostly rotary tools, such as discs, points, tubes, and rods. These tools may be composed of a variety of materials, depending on their intended use: from lac and wood—attested by Jawhari of Nishapur in his treatise, Jawaher-nama-ye Ne?ami, dated 592/1195-96 (Jawhari, p. 218)—through copper and soft iron.

 Kashani mentions, in connection with the cutting of rubies, wheels of lac, lead, wood, and copper (p. 42), and describes a long process of cutting, polishing, and tests, involving such abrasives as emery, shell, marcasite, and clay.

The myth that jade presents exceptional technical difficulties not encountered when dealing with other hardstones is remarkably persistent. Yet the technology is exactly the same as that used for other hardstones. Indeed, in some ways jade is easier to cut than, for example, the quartzes. Compared to them, not only is jade slightly less hard, but its toughness reduces the likelihood of breakage in the process of cutting, as well as later. Problems may arise at the polishing phase of finishing jade pieces, especially if a highly glossy surface is required, but these are neither significant nor insurmountable. Moreover, for most of the West Asian material, such a surface was never sought.

 

Terminology

 In Persian and Arabic literary sources, the words yashm, yashf, yashb, and ya?b are used for jade, though yashb and ya?b are generally understood to refer more precisely to jasper, a variety of cryptocrystalline quartz closely related to the chalcedonies such as carnelian and agate. Assadullah Souren Melikian-Chirvani (1997/2000, esp. pp. 123-26; cf. Pelliot, p. 424) has collected extensive material, tracing apparent cognates of these words to Old Babylonian and Old Assyrian texts. The overwhelming likelihood is that essentially all of the ancient Near Eastern use of yashpu/ashpu, even if cognate with yashf/yashb, must actually refer to the cryptocrystalline quartzes chalcedony (including agate) and jasper. This is borne out by any extensive survey of the thousands upon thousands of extant hardstone objects from the period in question.

In medieval Arabic, Persian, and Turco-Mongol sources, these purported properties are mainly apotropaic and medicinal, ranging from assuring victory in combat and protection from lightning to the prevention and cure of ailments of the internal organs. The modern English word jade is derived from the French pierre de l’éjade, resp. l’éjade and le jade, which in turn is derived from the Spanish piedra de ijada resp. hijada, a stone which cures internal ailments of the area of the small ribs resp. flanks. This was once seen as a cure for all sorts of colic, and became conflated with piedra de los ri?ones (kidney stone). In the sixteenth century, after the discovery of the use of jade in Central America, the stone “seems rapidly to have acquired a reputation as a treatment for kidney diseases” (Middleton and Freestone, p. 413). The eighteenth-century use of nephrite for jade reflects the same medicinal presumption, as it is derived from nephroi, the Greek word for kidneys (cf. Lat. lapis nephriticus: kidney stone).

Source: encyclopedia.thefreedictionary.com

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Other Links:

Seals and Sealings in Iranian History: part 1

Seals and Sealings in Iranian History: part 2

Seals and Sealings in Iranian History: part 3