Difference between revisions of "Jadeite" - New World Encyclopedia

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:''This article is about the mineral named jadeite. For the Sailor Moon character, see [[Shitennou (Sailor Moon)|Shitennou]].''
 
 
 
 
{{Infobox mineral
 
{{Infobox mineral
 
| name        = Jadeite
 
| name        = Jadeite
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| image      = chinese jadeite buttons.jpg
 
| image      = chinese jadeite buttons.jpg
 
| imagesize  =  
 
| imagesize  =  
| caption    = A selection of antique, hand-crafted Chinese jadeite buttons
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| caption    = A selection of antique, hand-crafted Chinese '''jadeite''' buttons
| formula    = NaAlSi<sub>2</sub>O<sub>6</sub><ref name="GRG">(Gia), Gemological. Gem Reference Guide. City: [[Gemological Institute of America]] (GIA), 1988. ISBN 0-87311-019-6</ref>
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| formula    = NaAlSi<sub>2</sub>O<sub>6</sub><ref name="GRG">Gemological Institute of America, ''Gem Reference Guide'' (Carlsbad, CA: Gemological Institute of America, 1988, ISBN 0873110196).</ref>
 
| molweight  =  
 
| molweight  =  
 
| color      = Semitransparent to opaque and often mottled, white, green, yellow to reddish orange, brown, gray, black, light purple or lavender.<ref name="GRG"/>
 
| color      = Semitransparent to opaque and often mottled, white, green, yellow to reddish orange, brown, gray, black, light purple or lavender.<ref name="GRG"/>
Line 26: Line 24:
 
| dispersion  =  
 
| dispersion  =  
 
| pleochroism = none<ref name="GRG"/>
 
| pleochroism = none<ref name="GRG"/>
| 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; <ref name="GRG"/>
+
| 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.<ref name="GRG"/>
 
| absorption  =
 
| absorption  =
 
| streak      =  
 
| streak      =  
 
| gravity    = 3.34 (+.06, -.09)
 
| gravity    = 3.34 (+.06, -.09)
 
| density    =  
 
| density    =  
| melt        =
 
| fusibility  =
 
| diagnostic  =
 
| solubility  =
 
| diaphaneity =
 
| other      =
 
 
}}
 
}}
'''Jadeite''' is a [[pyroxene]] mineral with composition NaAlSi<sub>2</sub>O<sub>6</sub>. It is [[monoclinic]]. It has a Mohs hardness of about 6.5 to 7.0 depending on the composition. The mineral is dense, with a specific gravity of about 3.4. Jadeitite forms solid solutions with other pyroxene endmembers such as [[augite]] and [[diopside]] (CaMg-rich endmembers), [[aegirine]] (NaFe endmember), and [[kosmochlor]] (NaCr endmember). Pyroxenes rich in both the jadeite and augite endmembers are known as [[omphacite]].
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'''Jadeite''' is one of the minerals recognized as the gemstone [[jade]].<ref>The other mineral recognized as "jade" is [[nephrite]], a green [[amphibole]].</ref> Its color commonly ranges from white through pale apple green to deep green, but it can also be blue-green (like the famous, rediscovered "Olmec blue" variety), pink, lavender, and a host of other rare colors.
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{{toc}}
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== Formation ==
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Jadeite is a [[pyroxene]] mineral with composition NaAlSi<sub>2</sub>O<sub>6</sub>. It is formed in [[metamorphic rock]]s under high pressure and relatively low temperature conditions. [[Albite]] (NaAlSi<sub>3</sub>O<sub>8</sub>) is a common mineral in the Earth's crust, with a [[density|specific gravity]] of about 2.6, much less than that of jadeite. With increasing pressure, albite breaks down to form the high-pressure assemblage of jadeite plus [[quartz]]. Minerals associated with jadeite include [[glaucophane]], [[lawsonite]], [[muscovite]], [[aragonite]], [[serpentine]], and quartz.
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Rocks that consist almost entirely of jadeite are called [[jadeitite]]. In all well-documented occurrences, jadeitite appears to have formed from [[subduction zone]] fluids in association with [[serpentinite]] (Sorensen et al. 2006). Jadeitite is resistant to weathering, and boulders of jadeitite released from the serpentine-rich environments in which they formed are found in a variety of environments.
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 +
Currently, the best-known sources of gem-quality jadeite are [[California]], [[Myanmar]] (Burma), [[New Zealand]], and (more recently) [[Guatemala]]. Other localities of jadeite include [[Kazakhstan]], [[Russia]], [[British Columbia]], [[Alaska]], and [[Turkestan]].
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 +
== Characteristics ==
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 +
Jadeite is composed of [[monoclinic]] [[crystal]]s. Their colors are largely affected by the presence of trace elements, such as chromium and iron. The crystals can be anywhere from entirely solid through opaque to almost clear. Variations in color and translucence are often found even within a single specimen.
 +
 
 +
This mineral has a Mohs hardness of about 6.5 to 7.0 depending on its composition. It is dense, with a specific gravity of about 3.4. Jadeitite forms solid solutions with other pyroxene endmembers such as [[augite]] and [[diopside]] (calcium and magnesium-rich endmembers), [[aegirine]] (sodium and iron-rich endmember), and [[kosmochlor]] (sodium and chromium-rich endmember). Pyroxenes rich in both the jadeite and augite endmembers are known as [[omphacite]].
  
Jadeite is formed in [[metamorphic rock]]s under high pressure and relatively low temperature conditions. [[Albite]] (NaAlSi<sub>3</sub>O<sub>8</sub>) is a common mineral of the Earth's crust, and it has a specific gravity of about 2.6, much less than that of jadeite. With increasing pressure, albite breaks down to form the high-pressure assemblage of jadeite plus [[quartz]]. Minerals associated with jadeite include: [[glaucophane]], [[lawsonite]], [[muscovite]], [[aragonite]], [[serpentine]], and [[quartz]].
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== Varieties and value ==
  
Rocks that consist almost entirely of jadeite are called [[jadeitite]]. In all well-documented occurrences, jadeitite appears to have formed from [[subduction zone]] fluids in association with [[serpentinite]], as discussed by Sorensen et al. (2006). Jadeitite is resistant to weathering, and boulders of jadeitite released from the serpentine-rich environments in which they formed are found in a variety of environments.  
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Jadeite from the Motagua Valley, [[Guatemala]], is the stone used by the [[Olmec]], [[Mayan Civilization|Maya peoples]], and indigenous peoples of [[Costa Rica]]. Typically, the colors of jadeite most valued are the intensely green, translucent varieties, though traditionally white has been considered the most valuable of the jades by the Chinese, known for their carefully crafted jade pieces.
  
Jadeite's color commonly ranges from white through pale apple green to deep [[jade (color)|jade'' green]] but can also be blue-green (like the famous and recently rediscovered "Olmec Blue" jade), pink, lavender, and a multitude of other rare colors.  Color is largely affected by the presence of trace elements such as chromium and iron.  Its translucence can be anywhere from entirely solid through opaque to almost clear.  Variations in color and translucence are often found even within a single specimen.  Currently, the best known sources of gem quality jadeite are [[California]], [[Myanmar]], [[New Zealand]] and more recently [[Guatemala]]; other localities of jadeite include [[Kazakhstan]], [[Russia]], [[British Columbia]], [[Alaska]], and [[Turkestan]].
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Currently, the most highly valued variety of jadeite is known as "Imperial Green" jade, characterized by an emerald green color and a high level of translucence. It the most expensive gem in the world, carat-by-carat, costing more than [[diamond]]s. Olmec blue jade, characterized by its deep blue-green, translucent hue with white flecking, is also becoming more highly valued because of its unique beauty and historical use by the Mesoamerican [[Olmec]] and the peoples of [[Costa Rica]].<ref>Elizabeth Kennedy Easby, ''Pre-Columbian Jade from Costa Rica'' (New York: André Emmerich, 1968).</ref> The Olmec blue variety, however, was only recently rediscovered and is being minimally exploited by native Guatemalans. It is thus difficult to obtain and too rare and little-known to have attained great value as a [[gemstone]].
 
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Jadeite is one of the minerals recognized as the gemstone [[jade]]. The other is the green [[amphibole]], [[nephrite]]. Jadeite from the Motagua Valley, [[Guatemala]] is the stone used by the [[Olmec]], [[Maya peoples]], and the indigenous peoples of [[Costa Rica]]. Typically, the most highly valued colors of jadeite are the most intensely green, translucent varieties, though traditionally white has been considered the most valuable of the jades by the Chinese, known for their carefully crafted jade pieces.  Currently, the most highly valued variety of jadeite is known as "Imperial Green" jade and is characterized by an emerald green color with a high level of translucence. It the most expensive gem in the world, carat-by-carat costing more than diamond. Other colors, like "Olmec Blue" jade, which is characterized by its deep blue-green, translucent hue with white flecking, are also becoming more highly valued because of its unique beauty and historical use by the Mesoamerican [[Olmec]] and also in [[Costa Rica]]<ref>Easby, Elizabeth Kennedy. ''Pre-Columbian Jade from Costa Rica''. (1968). André Emmerich Inc., New York</ref> ; however, this variety was only recently rediscovered and is only being minimally exploited by native Guatemalans. It is thus difficult to obtain and as yet too rare and little known to have attained great value as a gemstone. When purchasing jade, quality is determined by the degree of translucence, cleanness of color, and purity of color. Occasionally, other minerals like [[serpentine]] or [[quartz]] are sold as jade but the difference can be determined by cleavage and hardness.
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When purchasing jade, quality is determined by the degree of translucence, cleanness of color, and purity of color. Occasionally, other minerals like [[serpentine]] or [[quartz]] are sold as jade but the difference can be determined by cleavage and hardness.
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== See also ==
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* [[Amphibole]]
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* [[Jade]]
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* [[Mineral]]
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* [[Pyroxene]]
  
 
== Notes ==
 
== Notes ==
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==References==
 
==References==
  
* 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).
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* Farndon, John. 2006. ''The Practical Encyclopedia of Rocks & Minerals: How to Find, Identify, Collect and Maintain the World's best Specimens, with over 1000 Photographs and Artworks''. London: Lorenz Books. ISBN 0754815412
 +
 
 +
* Klein, Cornelis, and Barbara Dutrow. 2007. ''Manual of Mineral Science'', 23rd ed. New York: John Wiley. ISBN 0471721573
 +
 
 +
* Pellant, Chris. 2002. ''Rocks and Minerals''. Smithsonian Handbooks. New York: Dorling Kindersley. ISBN 0789491060
 +
 
 +
* Shaffer, Paul R., Herbert S. Zim, and Raymond Perlman. 2001. ''Rocks, Gems and Minerals''. Revised ed. New York: St. Martin's Press. ISBN 1582381321
 +
 
 +
* Sorensen, Sorena, George E. Harlow, and Douglas Rumble. 2006. “The origin of jadeitite-forming subduction-zone fluids: CL-guided SIMS oxygen-isotope and trace-element evidence.''American Mineralogist'' 91: 979-996.
 +
 
 +
== External links ==
 +
All links retrieved November 6, 2021.
 +
* [http://www.mindat.org/min-2062.html Jadeite] &ndash; Mindat.org.  
  
 
[[Category:Physical sciences]]
 
[[Category:Physical sciences]]

Latest revision as of 12:38, 6 November 2021

Jadeite
Chinese jadeite buttons.jpg
A selection of antique, hand-crafted Chinese jadeite buttons
General
Categorymineral variety of pyroxene
Chemical formulaNaAlSi2O6[1]
Identification
ColorSemitransparent to opaque and often mottled, white, green, yellow to reddish orange, brown, gray, black, light purple or lavender.[1]
Crystal habitmassive[1]
Crystal systemmonoclinic[1]
Fracturegranular to splintery[1]
Mohs Scale hardness6.5 - 7[1]
Lusterdull[1]
Refractive index1.666 - 1.680 (+/- .008); spot reading is 1.66[1]
Optical PropertiesDouble refractive with anomalous aggregate reaction [1]
Birefringenceusually not detectable[1]
Pleochroismnone[1]
Specific gravity3.34 (+.06, -.09)

Jadeite is one of the minerals recognized as the gemstone jade.[2] Its color commonly ranges from white through pale apple green to deep green, but it can also be blue-green (like the famous, rediscovered "Olmec blue" variety), pink, lavender, and a host of other rare colors.

Formation

Jadeite is a pyroxene mineral with composition NaAlSi2O6. It is formed in metamorphic rocks under high pressure and relatively low temperature conditions. Albite (NaAlSi3O8) is a common mineral in the Earth's crust, with a specific gravity of about 2.6, much less than that of jadeite. With increasing pressure, albite breaks down to form the high-pressure assemblage of jadeite plus quartz. Minerals associated with jadeite include glaucophane, lawsonite, muscovite, aragonite, serpentine, and quartz.

Rocks that consist almost entirely of jadeite are called jadeitite. In all well-documented occurrences, jadeitite appears to have formed from subduction zone fluids in association with serpentinite (Sorensen et al. 2006). Jadeitite is resistant to weathering, and boulders of jadeitite released from the serpentine-rich environments in which they formed are found in a variety of environments.

Currently, the best-known sources of gem-quality jadeite are California, Myanmar (Burma), New Zealand, and (more recently) Guatemala. Other localities of jadeite include Kazakhstan, Russia, British Columbia, Alaska, and Turkestan.

Characteristics

Jadeite is composed of monoclinic crystals. Their colors are largely affected by the presence of trace elements, such as chromium and iron. The crystals can be anywhere from entirely solid through opaque to almost clear. Variations in color and translucence are often found even within a single specimen.

This mineral has a Mohs hardness of about 6.5 to 7.0 depending on its composition. It is dense, with a specific gravity of about 3.4. Jadeitite forms solid solutions with other pyroxene endmembers such as augite and diopside (calcium and magnesium-rich endmembers), aegirine (sodium and iron-rich endmember), and kosmochlor (sodium and chromium-rich endmember). Pyroxenes rich in both the jadeite and augite endmembers are known as omphacite.

Varieties and value

Jadeite from the Motagua Valley, Guatemala, is the stone used by the Olmec, Maya peoples, and indigenous peoples of Costa Rica. Typically, the colors of jadeite most valued are the intensely green, translucent varieties, though traditionally white has been considered the most valuable of the jades by the Chinese, known for their carefully crafted jade pieces.

Currently, the most highly valued variety of jadeite is known as "Imperial Green" jade, characterized by an emerald green color and a high level of translucence. It the most expensive gem in the world, carat-by-carat, costing more than diamonds. Olmec blue jade, characterized by its deep blue-green, translucent hue with white flecking, is also becoming more highly valued because of its unique beauty and historical use by the Mesoamerican Olmec and the peoples of Costa Rica.[3] The Olmec blue variety, however, was only recently rediscovered and is being minimally exploited by native Guatemalans. It is thus difficult to obtain and too rare and little-known to have attained great value as a gemstone.

When purchasing jade, quality is determined by the degree of translucence, cleanness of color, and purity of color. Occasionally, other minerals like serpentine or quartz are sold as jade but the difference can be determined by cleavage and hardness.

See also

Notes

  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 Gemological Institute of America, Gem Reference Guide (Carlsbad, CA: Gemological Institute of America, 1988, ISBN 0873110196).
  2. The other mineral recognized as "jade" is nephrite, a green amphibole.
  3. Elizabeth Kennedy Easby, Pre-Columbian Jade from Costa Rica (New York: André Emmerich, 1968).

References
ISBN links support NWE through referral fees

  • Farndon, John. 2006. The Practical Encyclopedia of Rocks & Minerals: How to Find, Identify, Collect and Maintain the World's best Specimens, with over 1000 Photographs and Artworks. London: Lorenz Books. ISBN 0754815412
  • Klein, Cornelis, and Barbara Dutrow. 2007. Manual of Mineral Science, 23rd ed. New York: John Wiley. ISBN 0471721573
  • Pellant, Chris. 2002. Rocks and Minerals. Smithsonian Handbooks. New York: Dorling Kindersley. ISBN 0789491060
  • Shaffer, Paul R., Herbert S. Zim, and Raymond Perlman. 2001. Rocks, Gems and Minerals. Revised ed. New York: St. Martin's Press. ISBN 1582381321
  • Sorensen, Sorena, George E. Harlow, and Douglas Rumble. 2006. “The origin of jadeitite-forming subduction-zone fluids: CL-guided SIMS oxygen-isotope and trace-element evidence.” American Mineralogist 91: 979-996.

External links

All links retrieved November 6, 2021.

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