HomeGrading Jadeite
The criteria for evaluating jadeite have evolved largely within China. As Hughes, Galibert, et al (2000: 2) comment, "jade connoisseurship is almost strictly a Chinese phenomenon." In a section on the pricing and valuation of jadeite, the web site of the Department of Geology at the University of Texas (www.geo.utexas.edu) warns that it is "a difficult subject best left to a jade expert." Over the past couple of decades a number of authors writing in English have discussed the criteria for evaluating finished jadeite (see Healey and Yu 1983; Ng and Root 1984; Ho 1996; Newman 1998; Ou Yang 1999; and Hughes, Galibert, et al 2000: 17-20).


Ng and Root (1984: 104-105) provide a colour "Jade Master Stone Chart" that divides jadeite into fifty different categories as well as providing illustrations of more and less desirable characteristics of jadeite. Thirty-five of the categories are for green stones, five for lavender, and the remaining ten for other colors. There is a "Color Grading Scale" using letters, from "A" to "E": A = exceptional. B = very good, C = good, D = fair, and E = acceptable. In addition the stones are given numbers. In the case of green jadeite in particular, this serves as an additional means of ranking, from "A1" (which would be called exceptional imperial/emerald green jadeite) to "E7" (which would be called acceptable melon green jadeite). Newman (1998: 105) reprints a similar chart provided by Mason-Kay that has only thirty-six categories.

Healey and Yu (1983: 1670) comment in general that "through extensive experience in the trade most jade dealers have a broad consensus of opinion on how the quality of a piece of jade should be graded." Hughes, Galibert, et al (2000: 18) have remarked that "while a number of fanciful terms have been used to describe jadeite, its evaluation is similar to that of other gemstones in that it is based primarily on the "Three Cs" – color, clarity, and cut (fashioning)." Adding that "unlike most colored stones, the fourth "C" – carat weight – is less important than the dimensions of the fashioned piece and that "two additional factors are also considered – the 'Two Ts' – translucency (diaphaneity) and texture." These characteristics are not judged equally, however. As noted by Miller (1999: 91), for instance: "A fine color without translucency can bring a high price, but high translucency without body color has little price." The web site of the Department of Geology at the University of Texas (www.geo.utexas.edu) adds that "design, craftsmanship and antiquity play equally important roles when evaluating carved objects." 

Color. Newman (1998: 100) states that "an intense green to medium-dark tone is the most valued. As the color becomes lighter, darker, more grayish or brownish or yellowish, the value decreases." Values in descending order for other colors are: lavender, red, yellow, white, and black. Both the charts by Ng and Root and Newman/Mason-Kay are linked to tables or commentary about the relative value of the stones (these will be discussed below). The Department of Geology at the University of Texas (www.geo.utexas.edu) notes that in regard to green jadeite: "the best 'imperial green' has been likened to the color of fine emerald... Next in value are somewhat lighter shades, then lavender, dark apple green, 'forest' or 'spinach', light apple green, and dirty or spotty green."

Hughes, Galibert, et al (2000: 18-19) break the color components for assessing jadeite into three categories: "hue (position on the color wheel), saturation (intensity), and tone (lightness or darkness). In assessing hue, they use the example of the pure emerald-green of the highest quality jadeite: "While its hue position is usually slightly more yellow than that of fine emerald and it never quite reaches the same intensity of color, the ideal for jadeite is a fine 'emerald' green. No brown or gray modifiers should be present in the finished piece." Saturation is considered an especially important criteria for assessing green and lavender jadeite: "The finest colors appear intense from a distance... Side-by-side comparisons are essential to judge saturation accurately." They mention a related quality called cui whereby the color is judged to be brilliant, sharp, bright, or hot. In regard to tone, "the ideal tone is medium – not too light or too dark."

Color Uniformity. The color is uniform in the highest quality jadeite. In general the more uneven the color the lower the value, but multi-colored jadeite can be expensive when colors are strong and distinct. The most desired combinations of colors are green and lavender, green and orange, and strong green and white ("moss-in-snow jade"). The Department of Geology at the University of Texas (www.geo.utexas.edu) notes that "the most highly prized colors are those that are pure, intense, and uniform."

Transparency. This quality is also referred to as translucency. The most valued jadeite is semi-transparent (sometimes called "honey jade") or highly translucent. Increasing opaqueness results in lower values. An exception is white jade. Its price is not much influenced by this factor.

Clarity. The best fashioned jadeite is free of flaws (e.g., cracks, inclusions, cloudy areas, or spots); it is free of inclusions or other clarity defects that are visible to the naked eye. Among common imperfections are mineral inclusions (these are often dark green, black, or brown, but may be other colors as well) and white spots. Ou Yang (1999) remarks that perhaps the most serious defects are healed or unhealed fractures. These can have an considerable impact on the value of the stone—in part because jadeite is believed by Chinese to symbolize durability and perfection.

Texture. This can range from fine to coarse. The finer the better. Hughes, Galibert, et al (2000: 19) note that
texture is intimately related to transparency. In the authors’ experience, typically the finer the texture is, the higher the transparency will be. Further, the evenness of the transparency depends on the consistency of the grain size. Our observations also suggest that coarse-grained jadeite tends to have more irregularities, blotches, or discolorations.

Ho (1996) discusses three categories that are commonly employed for fashioned jadeite: 1) fine or "old mine", medium or "relatively old mine", and coarse or "new mine". Texture plays a key role in this categorization (which is not any longer actually associated with whether the piece in question came from one of the so-called "old mines" or the "new mines", although it did to some extent at one time). Old mine jadeite is viewed as having a higher quality, being of finer grain size, and having greater luster and translucency.
One other factor to take into account is the recut recovery potential of a piece of jadeite that has been poorly cut or damaged. This is primarily an issue with larger pieces, such as bangle bracelets and larger beads. Finally, when examining a piece of jadeite or jadeite jewelry care should be taken to see if it has been repaired. This is especially true of bangle bracelets. The gluing can be very well disguised. DelRe (1992) mentions that ultra-violet fluorescence is a good method of detecting such repairs since the glues often fluoresce (usually appearing blue). Often, of course, the repair can simply be detected by magnification.



Grading Guatemalan Jadeite. Jades, S.A., has devised a system for grading Guatemalan jadeite that is similar to that used for Burmese jadeite. In its Catalog 2000, the company presents a color chart with forty-two categories, ranging from A to G across the top of the chart and from 1 to 6 down the chart (with 6 being of higher quality than 1). These are divided by color and quality and include various shades of green, white, lavender, black, and so forth. The top green stones appear on the left side of the chart under the A and are largely referred to as types of Maya imperial jadeite. Among these categories, an A4 stone is described as semi-translucent, an A5 as "medium bright semi-translucent", and an A6 stone as "intense and translucent". Within the B category is "Maya semi-Imperial" green jadeite. Other greens include "intense apple green" (which is translucent) and "pale apple green" as well as "dark green " (which is not translucent). There is also a "bright blue" that is really a bright blue-green (which is given a high grade) as well as translucent "dark Olmec blue-green" and "light Olmec blue-green" (these are graded lower). Lilac categories include "intense translucent lilac" at the top, down to "very pale lilac with white mottling" at the bottom. The top grade of black jadeite is characterized as including "galactic gold" coloring, whereas the lowest grades are merely gray, charcoal, and black.
翡翠种和色
 
 

 

 

翡翠的分級:

傳統老式的玉石分級總是以深色老坑,老坑,金絲種,新坑種,油青種,豆青種來形容,但是對消費者來說,可以說是太過於抽象,為了讓消費者能夠簡單且貼切了解玉石,以下提供新的分級法做參考。

一.質地(種)

1. 玻璃地:質地明亮、清澈、細膩。最重要的是具有類似寶石單一結晶體之"硬"的感覺,極少可見之石紋,若有可見之雜質則多為形凍石花、甘蔗渣或片狀之黑煙。 此種質地鑲起後常可見內部之反射光芒,有時會有"貓眼"現象。這個質地是所有種質中的最高等級,可謂千萬年不變。

2. 冰地:顧名思義,其結晶如冰塊或冰糖感覺,乾淨度頗高。質地亦頗細緻,但其感覺不如玻璃地來的凍、硬,這種質地鑲起後水頭相當好。

3. 化地:其質地正如"果凍"之半透明狀,但可見細微小石花、棉絮等。

4. 冬瓜地:質地亦接近半透明狀,感覺如煮熟後之冬瓜。

5. 糯米地:質地要透不透,具有如熟糯米之細膩感,一般所稱之芙蓉地與此質地接近。

6. 翻生地:質地類似糯米地,但玉肉中部份結晶如不熟之生米般出現飯渣。

7. 豆地:如豆般不太通透,透度只入表面二分,有非常多可見之棉柳,蒼蠅翅、稀飯渣等,此種質地在強光下照射一段時日後易起小白花,"嬌度"降低。

8. 白地:一般玉石結晶多呈白色與無色,白色又為最常見之色彩,前述之新廠玉多只到此級,此質地己無通透之意境可言,此質地與常稱之"瓷地"接近。

9. 芋頭地:白中略帶灰,色如芋頭般,底屬木。

10. 灰地:不透明,質地多纖維,色暗如香灰般,具沙性。

11. 烏地:質地呈黑褐色,不透明,底木。

12. 油地:種質冰、硬,感覺有油脂光澤浮於表面。一般顏色較墨綠之玉石較有機會出現上現象。

二. 顏色:

1.艷綠:綠色純、正、濃,但不帶黑色。

2.綠:綠色中微帶蓝色,以寶石學觀點稱之為綠中微蓝。正因其綠中微蓝之色,使其看起充滿冷靜之神秘感,給人較"沈"的感覺。

3.翠綠:綠色鮮活,若生於玻璃地中,如綠水般搖晃欲滴,顏色較艷綠淺,為標準綠色之代表。

4.陽綠:綠色鮮陽,微帶黃色,也因其那份黃味,故綠色中帶有亮麗之生命感。

5. 淡綠:綠色較淡,不夠鮮陽。

6. 濁綠:顏色較淡綠色為深,但略帶混濁感。

7. 暗綠:色彩雖濃但較暗,不鮮陽,唯仍不失綠色。

8. 黑綠:綠色濃至帶黑色。

9. 蓝色:色彩偏微蓝,微帶綠色,寶石學稱之為蓝中微綠。

10. 灰色:顏色不蓝、不綠、不黑,帶灰色。

11. 黃色:大多數的黃色來自內皮,黃色搭配的質地常為冬瓜地以上之玉種。

12. 紫色:與翡紅相對,生於霧者為翡紅,生於玉肉者多為樁(紫色)分為淡紫、紫色、艷紫、紫。

13. 白色:此種顏色在硬玉中最常見,當它生於化地以上為無色,生於豆地以下則白色顯現。

14. 翡紅:多出於內皮中,生於玉肉中者,多成絲狀分佈,亦有成片者,在裂縫中之紅色為鐵元素入侵結果。

15.黑色:無綠色,呈墨黑色。

16.三彩:白地上有二色者叫"福祿壽" ,有三色者叫"福祿壽喜"。

四大色系顏色說明圖(以小樹苗為例)

 

 


Appraising the value of a jadeite jade jewelry or a jade carving is one of the most demanding task as there is no international grading system like the 4Cs of diamond. However, among the jade collectors and connoisseurs there are always some universal 'standards' and benchmark whereby a jade piece can be evaluated on the basis of beauty and desirability. Though with a history as old as civilization the problems that there is no international grading system for jadeite jade can be attributed to the following:

1) Jade is more of an 'Asian' phenomenal originating in China about 5,000 years ago. Though there are a lot of collectors among Western people and other races the Chinese are still the predominant owners of jade;

2) Throughout the ages the Chinese are the hard working people who keep the trade to themselves and who are interested to make more money for themselves than to go into some non-profit area of research and development and breaking new frontiers of knowledge where jade is concerned. Unlike the Western counterparts where a lot of diamonds and gemstones research are supported by grants from universities, institutions and associations there are non among the Chinese fraternity though you can find a Chinese in every nook and corner of the earth. (No offence meant to Chinese as I am an immigrant Chinese too.)

3) No two pieces of jadeite jade are the same. Each piece of jadeite jade is a unique stone with varying translucency, color and texture. The color of two jade pieces cut from the same stone may differ even though their translucency and texture may be of almost the same quality. This makes evaluation difficult.

4) Translucency, color and texture cannot be measured scientifically on exact terms and to conduct an empirical study would involve few millions of combinations and the acquisition of many expensive samples. (Anyway who wants to conduct a study on low grade jade).

So the factors that determine the quality of a jadeite jade piece are TRANSLUCENCYCOLOR and TEXTURE which is not necessary of the same order. Evalucating a jade piece with these 3 factors must be taken as a whole. Of course, a highly priced jade would have excellent translucency, vivid color hue and extremely fine and compact grains.

Pic 1: Translucency though the light of a microscope. Pic 2: Vivid hue of green in a bangle. Pic 3 Very very fine compact grain in a rectangle peice of jade.

TRANSLUCENCY The more translucent a jade piece is the more valuable it is. For a top quality Imperial Jade the term used may be semi-transparent. Usually in translucenct jade there is still some minor clouds within the jade piece. Now do not be mistaken that a vivid color jadeite jade would mean that the translucency is being obscured by the color. A lively vivid color jadeite jade can still be very translucent. I have seen some black jadeite jade bangles (Yes black in color) which is very translucent though it is interspaced with some crystal clear colorless strips. Translucency also has great appeal to the eye as an object of beauty. Its luster is luminous, its surface well polished and there is a 'softness' in the jade piece. The most valuable piece of translucent jade is called 'glassy', that is, it looks like clear glass. Following behind the glassy grade is the 'icy' grade. Then we have the translucent, semi-translucent and opaque. One also has to be careful when evaluating translucency. Given a big boulder with an open polished window and the crust intact how do you shine a light through to see whether it is translucent or not? The best way is to use a fiber optic light and touch it against the jade. The optic light should be able to penetrate the jade piece totally if it is a pendant of say 1/4 inche or if it is a thick slab or boulder with an open window the light should penetrate as deep as possible.

COLOR Color in a jadeite jade should be of a vivid hue, saturated, lively and vibrant. A totally colorless jade, if it is a bangle or a pendant, would be the most highly prized and its value is much higher than an old mine Imperial green or lavender. Of course this is the rarest. A vivid hue of fresh green or lavender is much desired as it will add 'color' to the wearer. The color within a highly prized jade should be evenly spread and not blotched with dark spots or whitish clouds. Often times a combination of bi or tri colors are preferred especially in carving pieces.

TEXTURE The texture is the composition of the grains within a jade piece. The more grainy a jade piece is the bigger the monoclinic crystals and it looks 'dry'. The more compact the grain is the more it can take on a hard polish and the more luster will the jade be. Grains should be at least medium fine for a good piece of jade. The rule of the thumb is the more you can see the grain the less worth it is.

For the 3 factors there is no standard benchmark or text books to read on. One needs to acquire experience in the field, one needs to view a lot of jade pieces and one needs to be constantly updated on international auction houses like Sotheby or Christie's in Hong Kong where it is the major jade trading center.

The 3Cs and the 2Ts
Five criteria when valuing a piece of jade are the 3Cs – colour, clarity and cut, and the 2Ts – translucency and texture.

Colour 
This is the most important factor in the quality of jade. Fine jade is pure, intense, bright and evenly coloured.

While vivid emerald green is ideal, jade is usually slightly bluish or yellowish. A good mix between green, blue and yellow can give a bright green colour. Jade in pale green, yellowish green or deep bluish green is of lower value, especially when tinged with brown or grey.

Jade also comes in lavender (popular among the young and in the West), white, yellow, reddish brown, or black. Natural high-quality red jade and yellow jade are rare. Mottled yellow jade is often intensified by heat to produce a reddish brown colour.

Jade with two or more colours is also valuable. Jade with three colours ideally green, lavender and red – is called fu lu shou in Chinese, symbolising fortune, prosperity and longevity. The most precious is wufu linmen – jade with five colours: green, red, lavender, yellow and white.

Clarity 
Jade commonly has dark green, brown or black inclusions or white spots. But inclusions in fine jade should be invisible to the naked eye.

Pay special attention to cracks, for even the small ones can greatly affect the gem’s value. Small fractures inside a stone may go unnoticed without careful observation.

If a piece contains a large fracture or is broken, it is better to have it re-cut and re-polished to enhance its value. For example, a broken bangle can be cut into small cabochons or saddles. (Also known as horse saddle, a saddle is a piece of rectangular jade with rounded angles commonly set on top of a ring. The jade saddle is usually encircled in gold, occasionally embellished with small diamonds.)

Cut 
The best-quality jade is usually cut as cabochons. Other popular forms include beads, bangles and saddles.

While weight is not an important evaluation criterion, pay attention to thickness. Jade in dark green and of poor translucency may be cut thinly to allow light to pass through. This may help it appear more transparent, but the thin piece becomes more fragile.

Jade of lower quality is often carved to make mottling and inclusions less visible. Fine jade is seldom used in carvings.

Translucency and texture 
The finer the grain size, the higher the translucency and the value. There are in general, four types of textures. The glassy type (boli zhong in Chinese) has the finest grains. This is followed by icy (bing zhong); then powder (fen di) or bean (dou zhong); and the coarsest, grey type (hui di).

The most valuable is old-mine glassy jade (laokeng boli zhong), which is imperial green and highly transparent. Glassy-textured jade is of good value even if it does not possess a brilliant colour.

While the above key factors determine the value of natural jade, what does a smart consumer look for in a market flooded with treated jade and jade imitations?

Natural vs treated jadeite
In a classification system commonly used in the jade industry, jade can be categorised into three types. Type-A is natural jade; type-B is jade that has been bleached and impregnated with resin or wax to improve transparency; and type-C is dyed jade. Jade that is both impregnated and dyed is called B+C jade.

Many treated pieces have nice colours and transparency comparable to fine natural jade, yet their prices are much lower. Why then, don’t we buy the treated stone? You may, but their beauty doesn’t last long. Type-B jade is likely to crack over time as its internal structure has been damaged during treatment. Dyed jade will fade in colour, especially the greens.

The colour of treated jade is unnatural. Type-B jade has a waxy shine rather than a glassy lustre. Its colour looks unnaturally bright with the impurities removed. Solidifying resin or wax may result in small and irregular fractures on the surface which can be checked with a magnifier.

Coarse-grained jade such as the bean type usually has a better dyeing result since it’s easier for organic dyes to penetrate the piece. However, the colour tends to concentrate along grain boundaries and in surface cracks. A magnifier can help detect these.

Green glass and green plastic are used to produce jade imitations. They can be identified through traditional methods such as a “tongue test”. This involves putting the piece on the tongue; it feels warm if it is glass or plastic, and cool if it is jade.

You can also tell the difference by hand. Jade has a higher specific gravity, and you can feel its weight when you hold it. The lustre and light reflection of the imitations are also different from those of jade.

Street peddlers, and some touristy spots in China, often sell low-quality jade, composed by assembling green glass or plastic with pale jade, or by assembling several thin pieces of pale jade together. Look closely and you will find glue in between.

The evaluation of jade and identification of treated stones requires a good eye, knowledge of jade, and experience. The simplest way to buy quality jade is to visit a reputable jeweller. To boost consumer confidence, more and more jewellers are attaching gemological certificates to their jade pieces.

While no one can say for sure if jade really brings fortune or happiness to their owners, it is definitely a beautiful gem appreciated not only in the Orient, but also the whole world. 
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翡翠透明度

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