Jadeite

Jadeite
Jadeite from Myanmar
General
CategoryPyroxene group
Formula
(repeating unit)
NaAlSi2O6 or Na(Al,Fe3+)Si2O6
IMA symbolJd[1]
Strunz classification9.DA.25
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupC2/c
Identification
ColorApple-green, emerald-green, bluish green, leek-green, purplish blue, greenish white, white, black, may show green spots, rarely blue or violet; colorless in thin section. Often also banded.
Crystal habitCommonly massive, or fibrous, granular; prismatic crystals rare
TwinningSingle and lamellar twinning on [100] and [001]
CleavageGood on [110]
FractureSplintery
Mohs scale hardness6.5–7
LusterSubvitreous, pearly on cleavages
StreakWhite
DiaphaneityTranslucent
Specific gravity3.24 to 3.43
Polish lustervitreous to greasy[2]
Optical propertiesBiaxial (+)
Refractive indexnα = 1.654 – 1.673 nβ = 1.659 – 1.679 nγ = 1.667 – 1.693
Birefringenceδ = 0.013 – 0.020
Dispersionr > v; moderate to strong.
Ultraviolet fluorescenceDark 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 pyroxene mineral with composition NaAlSi2O6. It is hard (Mohs hardness of about 6.5 to 7.0), very tough, and dense, with a specific gravity of about 3.4. It is found in a wide range of colors, but is most often found in shades of green or white. Jadeite is formed only in the subduction zones of continental margins, where rock undergoes metamorphism at high pressure but relatively low temperature.

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.

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ a b (Gia), Gemological. Gem Reference Guide. City: Gemological Institute of America (GIA), 1988. ISBN 0-87311-019-6
  3. ^ "Handbook of Mineralogy : Jadeite Na(Al; Fe3+)Si2O6" (PDF). Rruff.geo.arizona.edu. Retrieved 25 January 2022.
  4. ^ "Jadeite: Mineral information, data and localities". Mindat.org.
  5. ^ "A to Z List". Webmineral.com.