JADE (nephrite)

( Fr- néphrite; Ger- Nephrit; Nor- nefritt; Rus- )

JADE (nephrite), ~ Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂.

A. Nephrite boulder (weight: just over 11,000 kgs – i.e., ca. 12 tons; actually, this is only one piece of a larger boulder that weighed approximately 18,000 kgs - i.e., ca. 20 tons) atop Polar Mountain, northwestern British Columbia, Canada; the face of boulder was wetted with water for this photograph. (© photo by Kirk Makepeace; courtesy The Jade West Group, Vancouver, British Columbia, Canada)

B. Nephrite replica of an "Inuksuk" (height - 13 cm) fashioned by Tony Wu from tumbled pieces of low grade nephrite from the Kutcho Creek Mine, British Columbia, Canada. In the field, inuksuks (the term means land mark or beacon) are similar to cairns but roughly resemble people. Several have been built to guide travelers along safe routes on both land and waterways, especially in the Arctic and northern Canada. Empress jade, Vancouver, Canada. (© photo by Kirk Makepeace; courtesy The Jade West Group, Vancouver, British Columbia, Canada)

C. Nephrite "Sorrero [sic (= Saguaro?!!)] cactus" (height - 13 cm) carved from jade from the Ogden Mountain Mine in north central British Columbia, Canada by an unknown Chinese artisan. (© photo by Kirk Makepeace; courtesy The Jade West Group, Vancouver, British Columbia, Canada)

DESCRIPTION: Amphibole jade when viewed microscopically can be seen to consist wholly or largely of compact masses of either foliated or matted, interlocked crystal fibers of nephrite; some so-called nephrite contains noteworthy amounts of such minerals as diopside, epidote (or clinozoisite or zoisite), plagioclase feldspar, and quartz as well as minor magnetite, pyrite, etc. -- e.g., some of the well-known Wyoming nephrite jade contains noteworthy amounts of albite, epidote, quartz, and zoisite. See THE JADES entry for colors and some of the other properties that pertain to both Nephrite and Jadeite jade.
    H. 6-6½ (typically not as hard as jadeite jade)
    S.G. 2.9-3.2
    Light transmission - subtransparent to opaque
    Luster - appears greasy or oily on polished surfaces
    Miscellany - remarkably "tough" -- i.e., widely recognized as tougher than jadeite, apparently because of the so-called interwoven nature of its constituent fibers; much of it is fibrous and appears chatoyant.

OTHER NAMES: Several names, such as greenstone, have been applied to nephrite jade. Jill Walker in the tome edited by Keverne (1992) lists "common trade names" -- i.e., adjectives for nephrite jade -- as follows:

Attractive nephrite - so-characterized nephrite jade from the Fraser River valley of British Columbia, Canada is a fine quality nephrite with included bright green masses that consist of mixtures of nephrite and chromium-bearing grossular (Johnson et al., 2000).
Axe or hatchet stone - obsolete terms based on the use of nephritic jade for fashioning tools.
Blossom jade - name given in the marketplace to nephrite jade apparently derived from boulders recovered from places such as Jade Cove on the Pacific coast south of Monterey, California (Ward, 1999).
Blue jade (Pacific blue jade, Vonsen blue jade) - names for a nephrite from the Vonsen Ranch in Marin County, California (Chesterman, 1951).
Genuine oriental jade - trade name sometimes given nephrite from Taiwan (Liddicoat, 1966).
Grave (or tomb) jade - burial pieces, commonly brownish or yellowish (apparently due to oxidation of contained iron), recovered from old grave sites or tombs.
Greenstone - misnomer applied " the early European miners in New Zealand" (www.westcoastjade.co.nz).
Hetian jade - an off-white nephrite characterized by colored -- e.g., orangish -- spots. Much of it has been recovered as pebbles from alluvial deposits in western and central western China -- i.e., in the Kunlun mountains.
Inanga - grayish nephrite.
Maori stone - typically rather dark green nephritic jade from New Zealand.
"Marsden flower jade" - jade "with accentuated yellow rind inclusions" from New Zealand (www.westcoastjade.co.nz).
Mint in Snow - another name -- see Blossom jade -- given in the marketplace to nephrite jade apparently derived from boulders recovered from places such as Jade Cove on the Pacific coast south of Monterey, California (Ward, 1999).
Mutton fat - translucent white to ecru colored nephritic jade.
New Zealand greenstone (also pounamu) - name sometimes used for nephrite from New Zealand. Some of this nephrite is said to include chlorite and/or epidote.
New Zealand jade - in some circles, nephite jade has been given this designation as distinct from jadeite jade which was termed Chinese jade (see.JADEITE entry).
"Pigeon's-eye" - Wyoming nephrite that is chatoyant, apparently due to tremolite-rich zones (Liddicoat, 1964-65).
Pink jade - name sometimes given to Wyoming jade that "owes its color to the presence of a variety of zoisite (thulite) and is a composite of zoisite, nephrite, and coarse-grained tremolite" (Madson, 1983).
Polar jade - nephrite jade, described as "break[ing] the nephrite colour mould by being bright, translucent, intense green, and harder than any other nephrite," that is said to occur on a "mountain-top twenty-five miles east of Dease Lake", British Columbia, Canada (Ward, 1999).
Pounamu - name applied by Maori to New Zealand nephrite jade (www.westcoastjade.co.nz)
Puddingstone jade - nodular-shaped masses of relatively light green nephrite surrounded by a darker green nephrite matrix.
Siberian jade - nephrite from the Lake Baikal region, Siberia, Russia.
Snowflake jade - name applied to Wyoming jades that "characteristically contain nephrite, coarse-grained tremolite, quartz, epidote or zoisite, and albite" (Madson, 1983).
Spinach jade - relatively dark green, commonly slightly grayish, nephritic jade.
Wyoming jade - name often given to nephrite from Wyoming.

USES: A particularly interesting use of Wyoming jade is for fashioning letter openers, steak knife sets, and sets of cutlery. -- Madson (1983) illustrates a set -- probably considered by many as kitsch -- of which he remarks, "The cutlery set shown ... (one of three sets manufactured in 1974) represents 200 hours of lapidary time. The blades ... were cut from a 160-pound olive-green block; the handles were cut from a smaller block of snowflake [jade]." See also the many things listed under the USES subheading in THE JADES introductory section. Another interesting jewelry-related use is "low-quality nephrite is so tough that it makes a resilient hammering anvil to use in the jewelry-making process." (Weldon, 2007) A non-jewelry/non-decorative use of which I recently learned was "as a burnisher for architectural drawings. ... The burnisher was the smooth object that polished the paper flat [where errors has ben scraped off] ... so you could continue drawing on it without blots." (Jack Campin, personal communication, 2008). Campin had one his father used and hopes to get it made into something that will be decorative.

OCCURRENCES: Diverse origins, such as fissure fillings and "pods," within some metamorphic rock terranes and as cobbles and boulders in alluvium and other unconsolidated deposits derived from those rocks. . Most occurrences are associated with serpentine- and/or dolomite-rich rocks, with the most significant commercial deposits occurring in the dolomitic rocks -- see, for example, Yui and Kwon (2002), who describe the Chuncheon deposit in north-central Republic of Korea. Shigley et al. (2010) include several world-wide localities in their list "localities of the 2000s." Adamo and Bocchio (2013) describe and illustrate gems and carvings as well as the characteristics and occurrence of nephrite from Val Malenco in the Rhetic Alps, in Italy, near the border of Switzerland.

NOTEWORTHY LOCALITIES: The Polar and Kutcho mines, located east of Dease Lake in northern British Columbia, Canada is currently the world's major producer of nephrite. Other localities that are especially well known are Hetian, Xinjiang Province, China (especially for white nephrite); the Kuen-lun Mountain range on the Tibet-China border; south of Irkutsk, Lake Baikal region, Russia; near Jordanów, Poland (formerly Jordansmühl, Silesia); Taiwan; New Zealand -- e.g., near Milford Sound on South Island; along Dahl Creek near the far north villages of Kobuk and Shugnak (an Eskimo word for jade), Alaska; Mariposa, Monterey and Placer counties, California; [and] the Granite Mountains east of Lander, Wyoming. Shigley et al. (2000) tabulate localities and pertinent references for virtually all localities from which nephrite jade was recovered during the 1990s. See also Yui and Kwon (2002) and Shigley et al. (2010, p.210-211). A rather definitive study of nephrite from Guangxi Province of southern China (i.e., west of Hong Kong) is given by Yin et al. (2014).

REMARKS: The name, nephrite, is from the Greek nephros (kidney) via Latin Lapis nephriticus (kidney stone), and appears to have been based on the ancient belief that it served as a remedy so far as aleviating or curing kidney diseases. Although nephrite has been "discredited" so far as referring to any known mineral species by the CNMMN [Commission on New Minerals and Mineral Names] of the IMA [International Mineralogical Association], it seems likely that it will persist in the world of gemology.

Nephrite jade does not take up dyes as readily as jadeite jade; nonetheless, it has on occasion been dyed as well as otherwise treated; examples are light colored varieties that have been dyed green, carvings that have been "artistically stained to enhance the detail" (see Koivula and Kammerling 1990, p.309), and many pieces that have been waxed or oiled.

Some nephrite jade tends to become dull with the passage of time.

Over the ages, nephrite, apparently because of its great toughness, found wide use as tools, including sacrificial knives and weapons, in China, central Europe, New Zealand and in the Americas, especially in what are now known as Guatemala, Mexico and the southwestern United States.

The sarcophagus for Czar Alexander III was carved from nephrite jade.

Apparently jade items first fashioned from nephrite jade from the well known occurrences in central Wyoming was cut and polished in 1908 and 1909 in Salinas, California. The rough material is said to have been procured from Wyoming cowboys who were spending their winter in California (McFall, 1980). The Diplodocus Bar, in Medicine Bow, Wyoming features a "solid jade" bar that is about 40 feet long and carved from a single piece -- reported to be a 4 1/2 ton boulder -- of jade from the well-known Lander locality.

Cat's eye nephrite has been recorded from the area along the Kobuk River, south of the Brooks Range of Alaska (Sinkankas, 1955).

Nephrite jade is the official state gemstone of Wyoming and the "provincial stone" of British Columbia.

SIMULANTS: See those given in THE JADES introduction entry.

In addition, it seems noteworthy that so-called low-grade nephrite has been treated and marketed as highly sought kinds of nephrite -- e.g. low-quality nephrite has been treated by dying etc. to make it resemble Hetian jade (q.v.). See Zhang et al. (2011).

REFERENCE: Madson, 1983; Yui and Kwon, 2002.

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