Thulite and Holmquistite Optical Properties

Thulite

Holmquistite

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1 Optical Properties

1.1 Luster

Vitreous

1.2 Pleochroism

Present

Strong in shades of violet when dark-colored.Anthony et al

1.3 Dispersion

NANA

0.007 1

1.4 Transparency

Opaque, Translucent, Opaque . May be translucent in thin backlit sections.

Transparent

1.5 Refractive Index

1.6951.622-1.666

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Orthorhombic

Orthorhombic Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: P nma

1.8 Birefringence

0.006-0.018Not Available

0 0.296

1.9 Clarity

OpaqueHerve Nicolas Lazzarelli

Transparent

Thulite and Holmquistite Optic Character

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

Similar to their colors, Thulite and Holmquistite 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, Thulite is Opaque, Opaque . May be translucent in thin backlit sections. and Translucent while Thulite is Opaque, Opaque . May be translucent in thin backlit sections. and Translucent in appearance.