Jadeite - NaAl(SiO3)2

The name jadeite is derived from the Spanish phrase "piedra de ijada" which means "stone of the side". It was believed to cure kidney stones if it was rubbed against the side of the afflicted person's body. The Latin version of the name, lapis nephriticus, is the origin of the term nephrite, which is also a variety of jade. Jadeite composition commonly approach the ideal formula (NaAlSi2O6); it is the structural anolag of diopside CaMg(SiO3), and an incomplete series probably exists where Na+ and Al3+ replace Ca2+ and Mg2+. Chemically, jadeite lies intermediate between albite Na(AlSi3)O2 and nepheline Na(AlSi)O4.

Jadeite appears only in metamorphic rocks and is most common as a monomineralic rock. It is most characteristic of high uniform pressure and relatively low temperature but appears also in low-grade metamorphic rocks. It can form by a reaction of albite to produce :

NaAlSi3O8 (albite) = NaAlSi2O6 (jadeite) + SiO2 (quartz)





Optical properties:

• Form: Usually occurs as fine, fibrous aggregates.
• Color: Colourless.
• Relief: Moderate.
• Interference colors: Low, first order yellow.


jadeite2020(1).jpg

Green massive jadeite crystals, Myitkyina-Mogaung District, Kachin State, Myanmar (Burma). From RRUFF.




jadeite2020(2).jpg

Green massive jadeite crystals, Myitkyina-Mogaung District, Kachin State, Myanmar (Burma). From RRUFF.




Bibliography



• Bucher, K., & Grapes, R. (2011). Petrogenesis of metamorphic rocks. Springer Science & Business Media.
• Fossen, H. (2016). Structural geology. Cambridge University Press.
• Howie, R. A., Zussman, J., & Deer, W. (1992). An introduction to the rock-forming minerals (p. 696). Longman.
• Passchier, Cees W., Trouw, Rudolph A. J: Microtectonics (2005).
• Philpotts, A., & Ague, J. (2009). Principles of igneous and metamorphic petrology. Cambridge University Press.
• Shelley, D. (1993). Igneous and metamorphic rocks under the microscope: classification, textures, microstructures and mineral preferred-orientations.
• Vernon, R. H. & Clarke, G. L. (2008): Principles of Metamorphic Petrology. Cambridge University Press.
• Vernon, R. H. (2018). A practical guide to rock microstructure. Cambridge university press.


Photo
jadeite2017(1).jpg

Prismatic-fibrous jadeite crystals (colorless). PPL image, 2x (Field of view = 7mm)		 jadeite2017(2).jpg

Prismatic-fibrous jadeite crystals (high interference colors). XPL image, 2x (Field of view = 7mm)		 jadeite2017(3).jpg

Prismatic-fibrous jadeite crystals (colorless). PPL image, 2x (Field of view = 7mm)
jadeite2017(4).jpg

Prismatic-fibrous jadeite crystals (high interference colors). XPL image, 2x (Field of view = 7mm)		 jadeite2017(5).jpg

Prismatic-fibrous jadeite crystals (colorless). PPL image, 2x (Field of view = 7mm)		 jadeite2017(6).jpg

Prismatic-fibrous jadeite crystals (colorless). PPL image, 2x (Field of view = 7mm)
jadeite2017(7).jpg

Prismatic-fibrous jadeite crystals (high interference colors). XPL image, 2x (Field of view = 7mm)		 jadeite2017(8).jpg

Prismatic-fibrous jadeite crystals (colorless). PPL image, 2x (Field of view = 7mm)		 jadeite2017(9).jpg

Prismatic-fibrous jadeite crystals (high interference colors). XPL image, 2x (Field of view = 7mm)
jadeite2017(10).jpg

Prismatic-fibrous jadeite crystals (colorless). PPL image, 2x (Field of view = 7mm)		 jadeite2017(11).jpg

Prismatic-fibrous jadeite crystals (colorless). PPL image, 2x (Field of view = 7mm)		 jadeite2017(12).jpg

Prismatic-fibrous jadeite crystals (high interference colors). XPL image, 2x (Field of view = 7mm)
jadeite2017(13).jpg

Prismatic-fibrous jadeite crystals (colorless). PPL image, 2x (Field of view = 7mm)		 jadeite2017(14).jpg

Prismatic-fibrous jadeite crystals (high interference colors). XPL image, 2x (Field of view = 7mm)		 jadeite2017(15).jpg

Prismatic-fibrous jadeite crystals (colorless). PPL image, 2x (Field of view = 7mm)
jadeite2017(16).jpg

Prismatic-fibrous jadeite crystals (colorless). PPL image, 2x (Field of view = 7mm)		 jadeite2017(17).jpg

Prismatic-fibrous jadeite crystals (colorless). PPL image, 2x (Field of view = 7mm)		 jadeite2017(18).jpg

Prismatic-fibrous jadeite crystals (high interference colors). XPL image, 2x (Field of view = 7mm)
jadeite2017(22).jpg

Basal section of jadeite. PPL image, 10x (Field of view = 2mm)		 jadeite2017(23).jpg

Basal section of jadeite. PPL image, 10x (Field of view = 2mm)		 jadeite2017(24).jpg

Basal section of jadeite. XPL image, 10x (Field of view = 2mm)
jadeite2017(25).jpg

Basal section of jadeite. PPL image, 10x (Field of view = 2mm)		 jadeite2017(26).jpg

Basal section of jadeite. PPL image, 10x (Field of view = 2mm)		 jadeite2017(27).jpg

Basal section of jadeite. PPL image, 10x (Field of view = 2mm)
jadeite(5).jpg

Small gray fibrous jadeite crystals (replacing plagioclase) in a metagranite (Granulite facies), Sesia Valley, Piedmont, Italy. PPL image, 2x (Field of view = 7mm)		 jadeite(4).jpg

Small fibrous jadeite crystals (replacing plagioclase) in a metagranite (Granulite facies), Sesia Valley, Piedmont, Italy. XPL image, 2x (Field of view = 7mm)		 jadeite(7).jpg

Small gray fibrous jadeite crystals (replacing plagioclase) in a metagranite (Granulite facies), Sesia Valley, Piedmont, Italy. PPL image, 10x (Field of view = 2mm)
jadeite(12).jpg

Small gray fibrous jadeite crystals (replacing plagioclase) in a metagranite (Granulite facies), Sesia Valley, Piedmont, Italy. PPL image, 10x (Field of view = 2mm)		 jadeite(15).jpg

Small gray fibrous jadeite crystals (replacing plagioclase) in a metagranite (Granulite facies), Sesia Valley, Piedmont, Italy. PPL image, 10x (Field of view = 2mm)		 jadeite(17).jpg

Small gray fibrous jadeite crystals (replacing plagioclase) in a metagranite (Granulite facies), Sesia Valley, Piedmont, Italy. PPL image, 10x (Field of view = 2mm)