Jadeite
Jadeite | ||
---|---|---|
Specific gravity 3.24 to 3.43 | | |
Polish luster | vitreous to greasy[2] | |
Optical properties | Biaxial (+) | |
Refractive index | nα = 1.654 – 1.673 nβ = 1.659 – 1.679 nγ = 1.667 – 1.693 | |
Birefringence | δ = 0.013 – 0.020 | |
Dispersion | r > v; moderate to strong. | |
Ultraviolet fluorescence | Dark colors are generally inert. Light green – inert to weak white in long wave, generally inert in short wave; light yellow – inert to weak green in long wave, generally inert in short wave; white – inert to weak in long wave, generally inert in short wave; light purple – inert to weak white or weak brownish red in long wave, generally inert in short wave; some dyed lavender colors – moderate to strong orange in long wave, weaker in short wave[2] | |
References | [3][4][5] |
Jadeite is a
Jadeite is the principal mineral making up the most valuable form of jade, a precious stone particularly prized in China. Most gem-quality jadeite jade comes from northern Myanmar. Jade tools and implements have been found at Stone Age sites, showing that the mineral has been prized by humans since before the beginning of written history.
Name
The name jadeite is derived (via
Properties
Jadeite is a hard, extremely tough,
Jadeite has a
Jadeite is characterized by its green color and tough aggregates of compact fibrous crystals. It can be distinguished from nephrite by its vitreous luster on polished surfaces (polished nephrite has an oily luster)[9] and by its higher density and refractive index. Serpentine also has a lower density and refractive index than jadeite. Massive jadeite also characteristically shows a more granular texture than nephrite or serpentinite.[8]
Jadeite has a fusibility of 2.5 (making it moderately easy to fuse with a propane flame) and gives a yellow flame color.[8]
Pure jadeite has the composition NaAlSi2O6 and has the typical clinopyroxene structure. This consists of long chains of
Chemistry and origin
Pure jadeite has the composition NaAlSi2O6. There is no significant replacement of silicon by aluminium in natural jadeite, and only very limited substitution of ferric iron for aluminium.[9] However, calcium substitutes for up to 20% of the sodium, balanced by substitution of magnesium or ferrous iron for aluminium.[11]
Omphacite is intermediate in composition between jadeite and diopside.[9] However, there is not a true solid solution series, as omphacite has its own structure that is slightly different from either pure jadeite or pure diopside, so that it is separated from either end member by a miscibility gap.[11] Chloromelanite is a dark green variety of jadeite in which some aluminium is replaced by iron, while imperial jade, the most valuable variety of jade, is colored an intense emerald green by traces of chromium.[8]
Jadeite occurs with
-
+ →(Reaction 1)
Jadeite can also form at high pressure via the reaction:[9]
-
→ +(Reaction 2)
At still higher pressure, corresponding to the highest
-
+ → + +(Reaction 3)
Minerals associated with jadeite include:
Rocks that consist almost entirely of jadeite are called
Jadeitite is resistant to weathering, and alluvial boulders of jadeitite released from the serpentine-rich environments in which they formed can have weights of up to tons. Raw specimens having Burmese tax stamps or polished slots for evaluating quality are prized by some collectors.[8]
Colors
Jadeite's color commonly ranges from white through pale apple green to deep
Occurrence
Significant occurrences of jadeite are isolated and rare.[15] It is found exclusively in high-pressure, low-temperature metamorphic rock of continental margins.[9] Here it may be found as pods or veins or as disseminated grains.[11] Deposits are found in Myanmar, the Alps, Russia,[16] California,[9] Japan,[17] and Guatemala.[8] In the Franciscan Complex of California, jadeite is associated with glaucophane, aragonite, muscovite, lawsonite, and quartz.[9] However, occurrences of lapidary quality are almost exclusive to Myanmar.[8] Stream boulders of the Uyu River remain an important source of jadeite.[18]
Uses
Jadeite is the dominant mineral of the most desirable variety of jade.[10] This was prized in traditional Chinese culture, where it was worked into a great variety of beautiful ornaments and utensils.[9]
Jadeite was also used by Stone Age peoples for implements and weapons.[9]
Jade received its name, "piedra de ijada" ("stone of the side"), because it was once thought to cure kidney ailments when applied to the side of the body.[8]
Jade
Jadeite is one of two minerals recognized as the
Jadeite from the
Unusual colors, like "Olmec blue" jade, which is characterized by its deep blue-green, translucent hue with white flecking, are becoming more highly valued because of its unique beauty and historical use by the Mesoamerican
Stone Age use
Over 180 axe heads made from jadeitite quarried in northern Italy in the
A great many jadeite beads and axe heads as well as the remains of jadeite workshops from the
See also
References
- S2CID 235729616.
- ^ ISBN 0-87311-019-6
- ^ a b "Handbook of Mineralogy : Jadeite Na(Al; Fe3+)Si2O6" (PDF). Rruff.geo.arizona.edu. Retrieved 25 January 2022.
- ^ "Jadeite: Mineral information, data and localities". Mindat.org.
- ^ "A to Z List". Webmineral.com.
- ^ "Jade | Etymology, origin and meaning of jade by etymonline". Etymonline.com.
- .
- ^ ISBN 0442276249.
- ^ ISBN 047157452X.
- ^ ISBN 0922152349.
- ^ ISBN 9780195106916.
- ^ Yardley 1989, p. 105.
- ^ Sorena Sorensen, George E. Harlow, and Douglas Rumble, The origin of jadeitite-forming subduction-zone fluids: CL-guided SIMS oxygen-isotope and trace-element evidence. American Mineralogist, v. 91, pp. 979-996 (2006)
- ^ "Chloromelanite". Mindat.org. Retrieved 25 January 2022.
- ISBN 9780199653065.
- S2CID 232433079.
- ^ "Itoigawa City, Niigata Prefecture, Chubu Region, Honshu Island, Japan". Mindat.org. Retrieved 2016-06-30.
- ^ Klein & Hurlbut 1993, p. 599.
- ^ Klein & Hurlbut 1993, pp. 598–599.
- ISBN 978-1-4684-6574-7.
- ^ Austin, G.T. (1994). Gemstones (PDF). US Department of the Interior, Bureau of Mines.
- ISBN 9781461539223.
- . Retrieved 24 December 2021.
- ^ Easby, Elizabeth Kennedy. Pre-Columbian Jade from Costa Rica. (1968). André Emmerich Inc., New York
- ^ "Jadeite axe-head". British Museum. Retrieved 21 November 2009.
- Wiltshire Heritage Museum. Archived from the originalon 25 April 2012. Retrieved 31 October 2011.
- ISBN 0-415-21329-0.
- ^ Kijima, Tsutomu. "翡翠製大珠の加工と流通". Tateshinakougen.gr.jp (in Japanese).
- ^ Pearson, Richard. "International Jomon Culture Conference Bulletin 1 2004 (English version)". Academia.edu. Retrieved 2016-06-30.
Sources
- Yardley, Bruce W. D. (1989). An Introduction to Metamorphic Petrology. Longman Earth Science Series. Harlow, Essex, England: Longman Scientific & Technical. ISBN 0-582-30096-7.
External links
- Media related to Jadeite at Wikimedia Commons