NEPHRITE AND JADEITE

The Two Minerals Known as Jade: Nephrite and Jadeite

In Chinese, the word yü, meaning precious stone, is used for a variety of hard stones although only two are thought of as true jade: nephrite and jadeite. Nephrite, a silicate of calcium and magnesium of the amphibole group, is a mineral with a fibrous crystalline structure. It is less hard than jadeite, and when polished has a soft oil-like appearance. Nephrite was the primary material used in ancient China. Jadeite, a silicate of sodium and aluminum within the pyroxene group, is a mineral with an interlocking granular structure that can take on a high-gloss, glass-like finish. Both nephrite and jadeite are colorless or white when free of foreign elements. The pale tones of white jade were the tones most valued by the ancient Chinese. However, due mainly to the presence of compounds of iron, chromium, and manganese, both minerals exhibit a wide range of colors. Mottled and veined effects are common. Frequently, the original colors of archaic jades have been affected by contacts with chemicals in the earth or other organic substances. Nephrite has a range of browns, grays and greens that rarely occur in jadeite. The color range for jadeite is diverse as well, including bright greens and lavender tones, which have become popular in recent years. Jadeite was not worked extensively in China prior to the eighteenth century. Thus, most objects created before the latter part of Qing era (1644-1911) are of nephrite. Despite all the chemical and physical differences, the two minerals cannot always be distinguished from one another without the use an electron microscope.

Neolithic Jade Disc " Bi "

In principle, the Bi-Disk is a carved, mostly a round Jade Disk, with one middle hole of most various size. It will be used as status symbol, for ritual and/orsymbolic purposes. The oldest pieces are dating from the Neolithic period (HongShan- and LiangZhu cultures) and are only scanty or not decorated at all. They have on both sides smooth surfaces only,

While all theories presented to date are speculative, we can forward one based upon the Warring States text Zhou li (Rites of Zhou), that " bi " are thought to represent symbols of heaven and were used in ancient rituals together with square tubes (cong) symbolizing the earth. "To worship heaven with a bi " explains their importance and use. " Bi " also symbolizes status of high social rank and sheds light on why many carved jades have been found in Zhou royal tombs. They are prominently found in varied qualities, quantities and sizes. Their ritual prominence stretches from the most ancient of Chinese history- Hongshan/Liangzhu/Longshan (4700-21900 BCE)/ Qi Jia cultures and on to the Zhou dynasty (3000-250 BCE) onwards.

Jade Cong

Cong , essentially tubes with a square cross-section and a circular hole, are among the most impressive yet most enigmatic of all ancient Chinese jade artifacts. Their function and meaning are completely unknown. Although they were made at many stages of the Neolithic and early historic period, the origin of the cong in the Neolithic cultures of south-east China has only been recognized in the last thirty years.

The cong is one of the principal types of jade artifacts of the Liangzhu culture (about 3000-2000 BC) around Lake Tai in Jiangsu province. Spectacular examples have been found at all the major archaeological sites. The main types of cong have a square outer section around a circular inner part, and a circular hole, though jades of a bracelet shape also display some of the characteristics of cong .

The principal decoration on cong of the Liangzhu period was the face pattern, which may refer to spirits or deities. On the square-sectioned pieces, like this example, the face pattern is placed across the corners, whereas on the bracelet form it appears in square panels. These faces are derived from a combination of a man-like figure and a mysterious beast.

J. Rawson, Chinese jade: from the Neolith (London, The British Museum Press, 1995, reprinted 2002)

TOOLS FOR WORKING JADE

Nephrite and jadeite are extremely difficult to fashion requiring a harder stone such as quartzite or diamond to abrade or "carve" it. Notwithstanding this challenging characteristic, the surfaces of Neolithic ritual jades of simple shape have a smooth and polished appearance. The highly sophisticated, abraded decorative motifs on others objects of the same period, however, are somewhat less refined in finish and often appear chipped under high magnification. Recent research supports several theories as to how objects of nephrite were worked ancient China, each related to techniques that require stages of production using abrasives, from the initial slicing of blocks or slabs of jade to the boring of holes and modeling of linear motifs. Openwork designs mark the final steps in the completion of an object. It is likely that a straight-edged-hand or gut-string saw was used to cut, slice, and pare the jade into a workable form. Quartzite crystals have been found on the surfaces of many Hongshan period (circa 3800-2700 BCE) and Liangzhu period (circa 3300-2250 BCE) jades, thus confirming that quartzite was one abrasive that was used with water when working surfaces. In addition to hand or gut-string saws, the list of tools probably included awls and tubular drills, which may have been of bamboo. Bamboo with quartzite as an abrasive was probably used to make the holes in ritual jades such as bi (disks) and cong (prismatic tubes), as the remaining elliptical marks, particularly noticeable in the hollowed-out centers of cong, suggest that type of tool. For the fashioning of fine details, archaeological discoveries suggest the use of awls made of flint and possibly sharks teeth. Tools for carving the delicate ornamentation of late-Zhou period (circa 3rd - 2nd centuries BCE) amulets and pendants, reflect the introduction of new iron tools and possibly even the diamond point, enabling carvers to attain a new, highly refined level of technical excellence.

Technical Details - Holes

Probably the single most valuable technical diagnostic is the manner in which holes were made. A number of different aspects are involved: which technique was used to make the hole; whether the hole was bored exclusively from one side of the material, or both; whether the finished hole was polished inside, or left raw; what shape hole resulted (in longitudinal cross-section), straight-sided, conical, et cetera.

The earliest hole-production technique is "pecking", in which small amounts of material were removed by repetitive blows; this technique appears to have been used only on hard-stones, as jade's resistance to fracture probably make this technique impossible to use on jade.

In late working, two techniques seem to have predominated for making holes: solid- and hollow-boring. In the former, a solid rod with the end coated in abrasive material (perhaps quartz sand in a grease matrix) was rotated, and eventually wore a hole through the piece. In the latter, a hollow rod (perhaps a piece of bamboo) was used instead, and a cylindrical piece of jade was "punched out". The former technique seems to have been the earliest, and been less common later on, but it seems to have lived on for the production of small-diameter holes. Perhaps the latter technique was preferred later on as, since less material had to be removed (particularly for larger holes).

In holes which are bored from both sides, if the resulted hole was not polished internally, it is usually possible to tell, from the traces left where the holes from each side met, which technique was used. Hollow-boring resulted in a small ridge where the two holes met, with the sides of the ridge meeting at a fairly obtuse angle. Solid-boring, with the resulting dome-shaped hole, results in a more prominent meeting-ridge (and thus a smaller through-hole, relative to the size of the hole at the surface of the material), where the two sides meet at a fairly acute angle.

Neolithic Jade C-Dragon	Neolithic Chinese C-Dragon 3000-5000 BC from the Langzhou culture of dark green jade with carved detail. Approx 12" x 13"h $3,200.00		Neolithic Jade Bi	Neolithic Chinese Jade Bi, Longzhou culture 3000-5000 BC of overall green jade with mineral inclusions on outer edge. Approx 12" x 15"h $2,200.00
Neolithic Jade Bi	Chinese Jade Bi 3000-5000BC of green jade with inclusions and erosion on outside edge. Approx 14 x 16h $1,800.00		Neolithic Jade Collered Bi	Outstanding Chinese Jade Bi with "collar" of very thick, dark green,mossy jade with interesting veins throughout. 3000 -5000BC Exceptional! Approx 14" x 17"h $2,500.00
Neolithic Jade	$0.00 SOLD!		Neolithic Jade Bi	Large, handsome Chinese Bi with overall inclusions over green jade 3000-5000 BC, Longzhou culture. Approx 16" x 18"h $2,600.00
Large Chinese Neolithic Jade	Chinese Jade Bi of exceptional size and rich bronze color with interesting veining from the Longzhou culture 3000- 5000BC. Approx 24" x 25"h $4,200.00		Neolithic Jade Blade	$0.00
Neolithic Jade Reaping Blade	$0.00		Neolithic Jade Blade	$0.00