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