Opal and Foitite Optical Properties

Opal

Foitite

Add ⊕

1 Optical Properties

1.1 Luster

Vitreous, Pearly

Vitreous

1.2 Pleochroism

None

Strong: pale lavender dark blueAnthony et al

1.3 Dispersion

NoneNA

0.007 1

1.4 Transparency

Transparent, Translucent, Transparent to translucent

TranslucentAnthony et al, Translucent

1.5 Refractive Index

1.37-1.52Not Available

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal

Trigonal Ditrigonal Pyramidal H-M Symbol (3m) Space Group: R 3m

1.8 Birefringence

Not AvailableNot Available

0 0.296

1.9 Clarity

Transparent

TranslucentAnthony et al

Opal and Foitite Optic Character

Opal and Foitite optical properties play a significant role while distinguishing these gemstones from each other. These properties are influenced by the Opal and Foitite 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 Opal and Foitite 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.

Compare Semi Precious Gemstones

Opal Vs Lehsunia

Opal Vs Alexandrite

Opal Vs Amethyst

Opal and Foitite Transparency

Similar to their colors, Opal and Foitite 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, Opal is Translucent, Transparent and Transparent to translucent while Opal is Translucent, Transparent and Transparent to translucent in appearance.