pargasite
green pargasite from the Hunza Valley in Pakistan
oval cut pargasite from Mogok in Burma
Detailed sheet
pargasite
It is named after the town of Pargas in Finland,, where it was discovered in 1814. A green variety comes from Vietnam and Pakistan.
The variety where iron replaces magnesium is called ferropargasite.
CHEMICAL CHARACTERISTICS
NaCa2(Mg,Al) Al2[Si6O22] (OH)2
aluminosilicate
PHYSICAL CHARACTERISTICS
Main color
brown
Other colors
grey, yellow, black, orange, green
the green variety is the most sought and is emerald green
Color of streak
grey, green
Luster
greasy, vitreous
Hardness
5.0 to 6.0
Density
3.05 to 3.20
Cleavage
perfect
Fracture
uneven
small flat portions on the cleavage
OPTICAL PROPERTIES
Transparency
translucent, transparent
green variety rarely transparent
Refractive index
1.630 - 1.650
Double refraction
0.020
definite, biaxial (-)
visible double refraction
Yes
Dispersion
-
Pleochroism
weak
Number of colors
3
visible to the green variety: yellow-green, emerald green, green-blue
Fluorescence
none
CRYSTALS PROPERTIES
prismatic can be flattened tabular or biterminal
crystals system
monoclinic
OTHER INFORMATIONS
APPROACHING GEMS
Exploited
sites
It is found in Mogok in Burma, in the Hunza Valley in Pakistan, in Afghanistan, Vietnam (Yen Bai), Tanzania, Sri Lanka, China, Chile, in Queensland, Australia, France in Auvergne, Bavaria, Germany, Finland, Greenland, United States (California, Arizona, Whashington State, Virginia, New Jersey …) and Canada (Quebec, Ontario, Labrador).
use in jewelry
The sought color is emerald green which is very rarely found in gem quality. No use in jewelry.
imitations and
treatments
It was synthesized, as a scientific experiment, in microscopic crystals.
Other
Gems
Venez visitez
notre site web
voillot-joaillier.fr
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