Fayalite and Alunite Optical Properties

Fayalite

Alunite

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1 Optical Properties

1.1 Luster

Vitreous, Resinous

Vitreous, Pearly

1.2 Pleochroism

Faint

Not Available

1.3 Dispersion

NANA

0.007 1

1.4 Transparency

TransparentAnthony et al, Handbook of mineralogy (2001)

Not Available

1.5 Refractive Index

1.827-1.8791.572

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Orthorhombic

Trigonal

1.8 Birefringence

0.042-0.0510.020

0 0.296

1.9 Clarity

TransparentAnthony et al

Not Available

Fayalite and Alunite Optic Character

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

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Fayalite and Alunite Transparency

Similar to their colors, Fayalite and Alunite 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, Fayalite is Handbook of mineralogy (2001) and TransparentAnthony et al while Fayalite is Handbook of mineralogy (2001) and TransparentAnthony et al in appearance.