Opal and Andalusite Optical Properties

Opal

Andalusite

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1 Optical Properties

1.1 Luster

Vitreous, Pearly

Vitreous, Greasy

1.2 Pleochroism

None

strongly trichroic

1.3 Dispersion

Albite Optical ..

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None

Rank: N/A (Overall)▶

0.02

Rank: 23 (Overall)▶

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Fluorite Optical Properties

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0.044 (Anglesite Opt..)

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1.4 Transparency

Transparent, Translucent, Transparent to translucent

Transparent, Translucent

1.5 Refractive Index

1.37-1.52

1.627-1.650

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal

Orthorhombic

1.8 Birefringence

Not Available

0.009-0.010

1.9 Clarity

Transparent

Opal and Andalusite Optic Character

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

Opal Vs Alexandrite

Opal and Andalusite Transparency

Similar to their colors, Opal and Andalusite 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.