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Alexandrite
Alexandrite

Petalite
Petalite



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Alexandrite
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Petalite

Alexandrite and Petalite Optical Properties

1 Optical Properties
1.1 Luster
Vitreous
Vitreous, Pearly
1.2 Pleochroism
Not Available
AbsentWalter Schumann
1.3 Dispersion
NA0.01
Fluorite Optical Properties
0.007 1
1.4 Transparency
Transparent, Transparent to nearly opaque
Gemmological Tables (2004) More from other references
1.5 Refractive Index
1.739-1.7701.502-1.523
Agate Opal
1 3.25
1.6 Optic Character
Biaxial/+
Not Available
1.7 Crystal System
Orthorhombic
monoclinic
1.8 Birefringence
0.007-0.0100.012-0.016
Achroite
0 0.296
1.9 Clarity
Transparent
TransparentUlrich Henn and Claudio C. Milisenda

Alexandrite and Petalite Optic Character

Alexandrite and Petalite optical properties play a significant role while distinguishing these gemstones from each other. These properties are influenced by the Alexandrite and Petalite Physical Properties like crystallographic symmetry, pleochroism,etc. in the crystal. Some of the optical properties are refractive index, luster, optic character, pleochroism etc. Prominent among these is Alexandrite and Petalite optic character. You might have noticed your gemologist rotating the gemstone while testing it. Rotating a gemstone along its optic axis helps in determining its optic character. Alexandrite has Biaxial/+ character.

Alexandrite and Petalite Transparency

Similar to their colors, Alexandrite and Petalite transparency can also be used as criteria for their primary identification. Although transparency cannot be the only criteria for gemstone identification, it can efficiently used in gemstone grading. Talking about their transparency, Alexandrite is Transparent and Transparent to nearly opaque while Alexandrite is Transparent and Transparent to nearly opaque in appearance.