38-1821-CO-PR-8451-16











Certificate number 38-1821-CO-PR-8451-16
Mineral Specie Corundum
Issue date 2016-05-11
Variety Sapphire
OriginNatural
Chemical composition Aluminium oxide
Crystal system Rhombohedral
Habit Hexagonal bypiramid in different inclinations. Both ends of many crystals are capped by flat basal faces
ColourAccording to GIA GEmSet: G 7/1 green, dark, grayish
Cutting StyleOval
Measurements9.04x7.01x3.97 mm
Weight2.46 ct
LusterVitreous
TransparencyTransparent
Refractive indices1.770 - 1.762
Birrefringence0.008
Optic sign-
Hardness9 Mohs
CleavageNone
Density3.90
Absortion spectra Due to iron
Picture
Spectra description Three close bands centred at 460 nm, 471 nm and 450 nm producing a generally dark wide band.
Comments
Straight colour bands.
Tiny particles forming feathers. Extremately tiny particles forming feathers. Darkfield illumination, 40X.
 
 



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