The Collector: Burma Jade Buying Guide

Jadeite Jade Buying Guide title image
By Richard W. Hughes

Introduction
The term jade is used for two different minerals, jadeite and nephrite. Only jadeite has value as a gem material in and of itself.

Color
For jadeite, the intensity of the green color, combined with a high degree of translucency are the key factors in judging value. Stones which are too dark in color or not so translucent are less highly valued. Ideally, color should be completely even to the unaided eye, without spotting or veins. In lower qualities, fine root- or vein-like structures that contrast with the body color of the stone may be considered attractive. However, dull veins or roots are less desirable. Any form of mottling, dark irregular specks, or blotches that detract from the overall appearance of the stone will reduce the value.

Hue, Saturation, And Tone illustration image

The three basic elements of any color are hue position (top), saturation and tone (bottom). Note that saturation and tone are interrelated. As saturation increases, so does tone (lower left). However, there reaches a point where increasing absorption of light (increasing tone) results in a decrease in saturation (lower right). Illustration © Richard W. Hughes

Translucency
This is another important factor in evaluating quality. The best jadeite is semi-transparent; opaque jadeite or material with cloudy patches typically has the least value. It is interesting to note that even if the overall color is uneven or low in saturation, jadeite can still be quite valuable if it has good transparency.

Texture
In jadeite, texture is intimately related to transparency. Typically, the finer the texture, the higher the transparency. Further, the evenness of the transparency depends on the consistency of the grain size.

Clarity
In terms of clarity, fine jadeite should be free from noticeable or distracting inclusion defects. This refers to imperfections that impair the passage of light. The finest jadeite has no inclusions or other clarity defects that are visible to the naked eye. Typical imperfections are mineral inclusions, which usually are black, dark green, or brown, but may be other colors. Black spots easily visible to the eye are a particular problem because the Chinese associate them with bad luck. White spots also are common, as are other intergrown minerals. The most severe clarity defects in jadeite are fractures (healed or unhealed), which can have an enormous impact on value because jadeite symbolizes durability and perfection. That said, virtually all jadeite has feathers that are visible under magnification.

Cut
Fine jadeites are usually cut as cabochons. Material used for cabochons is generally of higher quality than that used for carvings, although there are exceptions.
With cabochons, the key factors in evaluating cut are the contour of the dome, the symmetry and proportions of the cabochon, and its thickness. Cabochon domes should be smoothly curved, not too high or too flat, and should have no irregular flat spots. Proportions should be well balanced, not too narrow or wide, with a pleasing length-to-width ratio.

Fei-ts’ui
A 17.22-ct. Imperial jade ring. Courtesy Pala International; photo © John McLean

Prices
Next to certain rare colors of diamond (such as blue, pink and red), jadeite is the world‘s most expensive gem, with prices above even ruby and sapphire. The record price for a single piece of jadeite jewelry was set at the November 1997 Christie’s Hong Kong sale: Lot 1843, the “Doubly Fortunate” necklace of 27 approximately 15 mm jadeite beads, sold for US$9.3 million (see figure 25). Indeed, out of the top ten most expensive jewels sold worldwide by Christie’s in 1999, five out of ten were jadeite, including three of the top four. These auctions clearly show that jadeite is among the most valuable of all gemstones. The most valuable jadeites are those of high translucency and rich Cr-green color.
Nephrite has little value as a gem in and of itself, but carvings can be quite valuable.

Stone Sizes
While jadeite sometimes occurs in pieces of several tons or more, top cut jadeite of even five carats is large and quite valuable.

Jadeite Jewelry
Traditionally, when fine jadeite cabochons are mounted in jewelry, they are backed by metal. The metal acts as a foilback of sorts, increasing light return from the stone. Often, a silver-colored plating is added to the inside of this backing to further increase reflection. The metal generally contains a small hole in the center, so one can shine a penlight through the stone to examine the interior, or probe the back with a toothpick to determine the contours of the cabochon base. When this hole is not present, one needs to take extra care, as the metal may be hiding some defect or deception.

Name
The name “jade” is derived from piedra de hijada, the Spanish name for jade. The Spanish adventurers in the time of Cortes brought back the jade pieces which they found among the Indians. The Spanish translation means “stone of the flank or loins,” or “colic stone.” It is believed that the flat polished pebbles with rounded edges resembled the kidneys, and would, therefore, be efficacious in disorders of that organ. Hansford states that the Spaniards knew the stone as piedra de los rinones (‘kidney stone’), a name which was translated into Latin as lapis nephriticus and this gives the word nephrite.
In 1863, French mineralogist Alexis Damour analyzed bright green jades from Burma. When he found these samples to be different from what was called Chinese jade (usually amphibole jade, or nephrite), he named the mineral jadeite.



Top left: This jadeite boulder shows the relatively thin skin and potentially good color that is usually associated with “river jade.” Although from the outside this appears to be a normal jadeite boulder, oxidants that entered through cracks on the surface have produced a large area of discoloration. Bottom left: Note the thick yellow “mist” around the jadeite in this boulder of “mountain jade.” Right: A key advantage to jadeite taken from in situ deposits is that the quality of the material is readily apparent. Photos © Richard W. Hughes.

Sources
The most important source of gem quality jadeite is Upper Burma, near the small town of Hpakan. Today, virtually all top-quality jadeite is produced from these mines. Other jadeite localities include Guatemala, Russia, Kazakhstan, Japan and California, but all pale in comparison with Burma. No gem-quality jadeite is found in China. Ancient Chinese jade is nephrite, and was mined in far western China near Khotan. Nephrite is also produced in Taiwan, British Colombia, Alaska, Wyoming, Australia, Russia and New Zealand.

Enhancements
Today, the vast majority of jadeite is dipped in wax as a final finishing step. This is considered a normal trade practice. All other enhancements are considered abnormal and adversely affect value. Some jadeite is dyed green or other colors and these dyed colors may fade with time. Other jade is bleached and then impregnated with a polymer (b-jade). As with all precious stones, it is a good practice to have any major purchases tested by a reputable gem lab, such as the GIA or AGTA, to determine if a gem is enhanced.

Imitations
Synthetic jadeite was first produced by General Electric, and the process now produces material of quite fine quality. However, such material is rarely seen and is mostly experimental. Imitation jades abound. These include green glasses and natural gems such as hydrogrossular, serpentine and many others.

Lore
Among the various gems, no single stone has a closer relationship with a culture than jade with the Chinese. It is considered the “Stone of Heaven” and is thought to provide a bridge between this world and the next. Jade also played an important part in Mayan and Maori cultures. In each of the above cultures, jade was considered “beyond price.”

The above stone is a fine example of Burmese jadeite. Photo: Wimon Manorotkul

Properties of Jadeite Jade

	Jadeite Jade
Colors	Various shades of green, lavender, white, colorless, brown, orange
Composition	NaAlSi₂O₆
Hardness (Mohs)	6.5–7
Specific Gravity	3.34 (+ 0.06, –0.09)
Refractive Index	1.666–1.680 (±0.008); spot RI 1.66; birefingence usually not measurable
Optic Character	DR, Biaxial; aggregate polariscope reaction
Spectrum	Generally line at 437 nm; Cr-green may have lines at 630, 655, 690 nm
Crystal System	Monoclinic; occurs as massive polycrystalline aggregates
Fracture	Granular to splintery
Pleochroism	None
Phenomena	None
Handling	No special care needed for untreated jadeite; treated jadeite may be damaged by ultrasonic and/or steam cleaning; solvents, acids
Enhancements	Most jadeite is wax dipped; some jadeite is dyed and/or bleached and then polymer-impregnated
Synthetic available?	Yes, but quite rare in the market