sugilite
rough sugilite of south Africa
African sugilite cut in cabochon
Detailed sheet
sugilite
It was discovered in 1944 in Japan, its name honors the Japanese geologist Ken-ichi Sugi (1901-1948) who has identified it.
But it was not until the late 1970s that a purple manganiferous variety from South Africa has been used in jewelry.
There is also another kind of “sugilite”: a sometimes heterogeneous mixture of manganiferous sugilite with chalcedony.
Depending on the proportions of the mixture, the density varies and the refractive index gets closer to that of chalcedony towards 1.55 or to the sugilite one towards 1.60
Some stones may even have different refractive indices according to the sections examined.
CHEMICAL CHARACTERISTICS
KNa2(Fe,Mn,Al)2Li3[Si12O30]
cyclosilicate
PHYSICAL CHARACTERISTICS
Main color
purple
Other colors
blue, pink
purple blue and intense pink shades
Color of streak
white
Luster
vitreous
Hardness
6.0 to 6.5
Density
2.70 to 2.80
Cleavage
indistinct
Fracture
uneven
OPTICAL PROPERTIES
Transparency
opaque, translucent
Refractive index
1.605 - 1.611
Double refraction
0.001
very weak, uniaxial (-)
visible double refraction
No
Pleochroism
absent
Number of colors
1
Absorption spectrum
570 - 479 - 437 - 419 - 411
sugilite spectrum system
Fluorescence
none
CRYSTALS PROPERTIES
short prisms
crystals system
hexagonal
OTHER INFORMATIONS
Astrological sign
Leo, Sagittarius
APPROACHING GEMS
Exploited
sites
It is found in South Africa, in Tuscany, Italy, Australia, Mt St-Hilaire, Canada, India
use in jewelry
It is rarely faceted but often cut in cabochon for pendants, into balls for necklaces and also carved for decorative objects.
The most in demand varieties are those that are translucent and colorful in purple, they are called “sugilite gem” or “sugilite gel”.
Daily care
and precautions
it is certainly its robustness that helped this stone to find its place as a “gem”.
imitations and
treatments
It can be imitated by magnesite or dyed purple jade.
The purple lepidolite is also sometimes used to imitate it.
Some colored nephritis and serpentine are also used, and even resins and plastics.
Historical
healing properties
It would also be a shield stone protecting from negative waves that reach us, voluntarily or involuntarily.
Other
Gems
Venez visitez
notre site web
voillot-joaillier.fr
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