Opal and Astrophyllite Optical Properties

Opal

Astrophyllite

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1 Optical Properties

1.1 Luster

Vitreous, Pearly

Greasy, Pearly

1.2 Pleochroism

None

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

1.3 Dispersion

NoneNA

0.007 1

1.4 Transparency

Transparent, Translucent, Transparent to translucent

Translucent

1.5 Refractive Index

1.37-1.521.678-1.758

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal

Triclinic

1.8 Birefringence

Not Available0.050

0 0.296

1.9 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 Lehsunia

Opal Vs Alexandrite

Opal Vs Amethyst

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 Translucent, Transparent and Transparent to translucent while Opal is Translucent, Transparent and Transparent to translucent in appearance.