Opal and Astrophyllite Optical Properties

Opal

Astrophyllite

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Optical Properties

Luster

Vitreous, Pearly

Greasy, Pearly

Pleochroism

None

Strong: X= deep red-orange Y= orange-yellow Z= lemon-yellow

Dispersion

0.010.12

0.005 1

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Transparency

Transparent, Translucent, Transparent to translucent

Translucent

Refractive Index

1.37-1.521.678-1.758

1 3.25

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Optic Character

Crystal System

Trigonal

Triclinic

Birefringence

-99990.050

0 0.296

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Clarity

Transparent

Translucent

Opal and Astrophyllite Optic Character

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

Opal Vs Simpsonite

Opal Vs Spessartine

Opal and Astrophyllite Transparency

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