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Biotite
Biotite

Cordierite
Cordierite



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Biotite
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Cordierite

Biotite and Cordierite Optical Properties

Optical Properties

Luster

Vitreous, Pearly
Greasy, Vitreous

Pleochroism

Strong
X = pale yellow

Dispersion

-0.01
0.005 1
👆🏻

Transparency

-
-

Refractive Index

1.565-1.625-9999
1 3.25
👆🏻

Optic Character

-
-

Crystal System

monoclinic
Orthorhombic

Birefringence

0.03-0.07-9999
0 0.296
👆🏻

Clarity

-
-

Biotite and Cordierite Optic Character

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

Biotite and Cordierite Transparency

Similar to their colors, Biotite and Cordierite 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, Biotite is while Biotite is in appearance.