lazurite
lazurite from Afghanistan cut in cabochon
lazurite from Afghanistan cut in cabochon
Detailed sheet
lazurite
Discovered in 1890, its name comes from the Persian “Lazhward” which means blue. This is the main component of lapis lazuli, that gives it its beautiful ultramarine blue color. Pure crushed lazurite gives the blue pigment used since antiquity. The Egyptians went to Afghanistan to seek it at Sar-e-Sang in the valley Koksha in the current Badakhshan, Afghanistan.
CHEMICAL CHARACTERISTICS
(Na,Ca)8Al6[Si6O24](S,SO4,Cl2)
complex silicate
PHYSICAL CHARACTERISTICS
Main color
blue
Other colors
purple
ultramarine blue, sometimes purplish or greenish
Color of streak
blue
Luster
resinous, vitreous
Hardness
5.0 to 5.5
Density
2.35 to 2.45
Cleavage
indistinct
Fracture
conchoidal, uneven
very difficult cleavage
OPTICAL PROPERTIES
Transparency
opaque, translucent
very intense color
Refractive index
1.500 - 1.525
Double refraction
0.000
zero because isotropic but some polarization anomalies are possible
visible double refraction
No
Pleochroism
absent
Number of colors
1
Fluorescence
none
CRYSTALS PROPERTIES
dodecahedra, hexoctahedrals
crystals system
cubic
OTHER INFORMATIONS
APPROACHING GEMS
Exploited
sites
Apart from historical deposits of Afghanistan and Tajikistan, it is found in Canada on Baffin Island, Italy, Siberia near Lake Baikal, Slovakia, Sweden, United States (California, Arkansas, Colorado ).
use in jewelry
It was used since ancient times, in the Middle Ages it was used to prepare blue dyes and pigments for paints. Very expensive, it was often replaced with azurite. As the lapis lazuli, it is cut cabochon for rings. The lapis lazuli and lazurite are the stones for the anniversary of the ninth year of marriage.
Daily care
and precautions
It is fragile, gets damaged by bathing it in hot water, soap, acids. It must avoid contact with household cleaners and should be washed with warm water carefully, and dried immediately.
imitations and
treatments
This is the component which gives the beautiful color to lapis lazuli, it was often tried to imitate, but its ultramarine color is so distinctive when lazurite is pure, that it is very difficult.
Historical
healing properties
See lapis lazuli, lazurite being its principal constituent, they have a lot of common properties
Other
Gems
Venez visitez
notre site web
voillot-joaillier.fr
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